JP6742142B2 - Galvanized welded steel and method for producing galvanized welded steel - Google Patents

Description

The present invention relates to a galvanized welded steel shape and a method for producing a galvanized welded steel shape.

Various lightweight steel shapes such as welded lightweight H-section steel are known. Of these, the welded lightweight H-section steel is an H-section steel formed by using hot rolling steel strip, cold rolling steel strip, or galvanized steel strip and combining continuous high-frequency resistance welding or high-frequency induction welding. is there. Welded lightweight H-section steel is mainly used as a building structural material such as columns and beams of prefabricated houses and structures. In recent years, the welded lightweight H-section steel has been used not only as a steel structure but also as a material for pillars and beams in a wooden house of a conventional construction method, and its demand is expanding.

In recent years, welded lightweight H-section steel is being studied for use in severe outdoor corrosive environments, as represented by pedestal parts for photovoltaic power generation. When using the welded lightweight H-section steel in such an environment, there is a method of performing hot dip galvanizing on the welded lightweight H-section steel manufactured using a non-plated steel material in order to ensure corrosion resistance. However, there is a problem of shape change due to heat during plating and outsourcing cost, and it is expected to utilize a plated welded lightweight H-section steel formed by forming a plated steel strip as disclosed in Patent Document 1, for example.

JP, 2003-275814, A

The plated welded lightweight H-section steel as disclosed in the above Patent Document 1 utilizes a plated steel strip that has been subjected to a plating treatment in advance and is formed by the combined use of continuous welding. When welding the steel strip and the steel strip corresponding to the web, the plating layer at the welded portion is lost due to the heat generated. Further, when the steel strip corresponding to the flange is manufactured by the slit, the plating layer does not exist on the end surface of the flange.

It is important to apply anticorrosion treatment suitable for the application environment to welded parts and end faces where no plating layer is present, because damage due to corrosion is a concern. The establishment of is required.

Generally, the service life is considered to be proportional to the amount of plating applied, and in order to ensure the same level of corrosion resistance as plating on the flat surface, ensure that the same amount of plating metal component as the plating on the flat surface is deposited. Are considered important. From such a viewpoint, zinc-based thermal spraying and zinc powder-containing coating (hereinafter, also referred to as “zinc rich coating”) are conceivable as repair technology candidates for ensuring sufficient corrosion resistance. However, thermal spraying, which is a dry process, cannot be easily performed because dust countermeasure equipment is required. Therefore, Patent Document 1 also describes that zinc spray coating is performed on the welded portion.

On the other hand, for the zinc rich coating as disclosed in Patent Document 1 above, a standard construction technique has been established as an anticorrosion treatment specification. That is, the zinc rich coating has a problem that it contains a large amount of metallic zinc pigment and the remaining binder component is very small, so that it lacks adhesiveness and adheres only to a clean steel surface. Therefore, a high degree of base adjustment is required when applying zinc rich coating, and blasting is recommended. As an alternative to the blasting treatment, it is possible to use a pickling treatment or a power tool to adjust the foundation, but the adhesion is slightly inferior to the blasting treatment. In addition, zinc phosphate treatment, which is used as a base material for general coating, also reduces the adhesion of the zinc rich coating, and therefore cannot be used as a base material.

Despite the above situation, Patent Document 1 does not mention anything about the adjustment of the substrate when performing the zinc spraying process.

When blasting is performed to adjust the base material of the welded portion or end face of plating welded lightweight H-section steel to form a zinc rich coating film, the blasting treatment is also applied to the plated face located near the welded portion or end face. Will be done. In particular, when the blast treatment is performed on the end face, at least the plated surface on either the front side or the back side is greatly affected by the blast treatment. Therefore, in order to apply the zinc-rich coating film to improve the corrosion resistance of the weld and the end surface, the corrosion resistance of the plated surface located near the weld and the end surface is affected, and the base material prior to the formation of the zinc-rich coating film is obtained. It is considered that it is not preferable to adopt the blast treatment as the adjustment. Under such circumstances, there is a demand for a base adjusting technique which is an alternative to the blast treatment, particularly for a welded portion of plated welded lightweight H-section steel.

Further, the plating layer itself of the plated welded steel may be deteriorated depending on the surrounding environment. For example, it is known that the plating layer is oxidized by electrolyte such as salt contained in the atmosphere, oxygen and water existing in a high temperature and high humidity environment, and becomes white rust. Therefore, it is desirable to improve the corrosion resistance of the plating layer itself. The surface of the plating layer may be subjected to chemical conversion treatment for the purpose of rust prevention, and a chemical conversion treatment coating may be provided. As a result of the study by the present inventors, it was found that the chemical conversion treatment film affects the adhesion of the zinc-rich coating film when the zinc-rich coating film is formed on the welded portion or the end surface.

Therefore, the present invention has been made in view of the above problems, the object of the present invention is to improve the corrosion resistance of the plating layer, the corrosion resistance of the portion where the plating layer is missing, zinc powder containing It is an object of the present invention to provide a galvanized welded steel and a method for manufacturing a galvanized welded steel which can be realized while maintaining the adhesion of coating.

In order to solve the above problems, as a result of intensive studies by the present inventor, while arranging a coating film containing zirconium and an organic acid on the plating layer, through the resin film, zinc particles in the missing portion of the plating layer The inventors have come up with the idea of arranging an organic coating film containing, and have completed the galvanized welded steel and the method for producing a galvanized welded steel according to the present invention as described in detail below.
The gist of the present invention completed based on such knowledge is as follows.

(1) A web made of a zinc-based plated steel sheet which is a plated steel sheet having a pure zinc plated layer or a zinc alloy plated layer ,
A zinc-based plated steel sheet, which is a plated steel sheet having a pure zinc plated layer or a zinc alloy plated layer, and a flange welded to the web,
A weld bead located at the weld between the web and the flange,
A first coating located on the web and the flange, the first coating including zirconium and an organic acid;
A second coating that is positioned to cover at least a portion of the weld bead and at least a portion of the first coating and that includes a resin material;
An organic third coating which is a coating containing an organic resin which is a binder component and zinc particles, and which is positioned so as to cover the weld bead and at least a part of the second coating;
With galvanized welded steel.
(2) The plated welded steel according to (1), wherein the second coating has a thickness of 3 to 30 μm.
(3) The resin material is configured to include Epoxy resins, (1) or plated welding shaped steel according to (2).
(4) The first coating film contains 10 to 45 parts by mass of vanadium, 5 to 100 parts by mass of phosphorus, 0.1 to 20 parts by mass of cobalt, and 10 to 90 parts by mass of organic acid with respect to 100 parts by mass of zirconium. The galvanized steel section according to any one of (1) to (3), which is included in the ratio of parts.
(5) The third coating film is an organic coating film layer containing 60% by mass or more of zinc particles with respect to the total mass of the third coating film, (1) to (4). Galvanized welded steel described in.
(6) The plated welded steel according to any one of (1) to (5), wherein the thickness of the third coating film is 5 to 200 μm.
(7) The second coating is located on at least a portion of the end surface of the flange and at least a portion of the first coating adjacent to the end surface,
The plated welded shaped steel according to any one of (1) to (6), wherein the third coating is positioned on the second coating so as to cover the end surface of the flange.
(8) The plating welding form according to any one of (1) to (7), further including a coating film containing a bright pigment, which is positioned so as to cover at least a part of the third coating film. steel.
(9) The plating according to any one of (1) to (8), which is a plating welded H-section steel in which a pair of flanges including the flange are arranged so as to face each other via the web. Welded steel.
(10) and the web made of galvanized steel sheet is a plated steel sheet having a pure zinc plated layer or zinc alloy plating layer, made of zinc-plated steel sheet is a plated steel sheet having a pure zinc plated layer or zinc alloy plating layers, wherein A plating comprising a flange welded to a web, a weld bead located at a welding site between the web and the flange, and a first coating formed on the web and the flange and containing zirconium and an organic acid. A second coating including a resin material is formed on the welded shaped steel to cover at least a part of the weld bead and at least a part of the first coating, and the second coating is formed. it is the plated welding shaped steel aged at least 4 hours or more with, and covers the weld bead, and covers at least a portion of said second coating is the coating comprising an organic resin and zinc particles is the binder component A method for producing a plated welded steel shape, which comprises forming an organic third coating film.

As described above, according to the present invention, while improving the corrosion resistance of the plating layer, while maintaining the adhesion of the zinc powder-containing coating, the corrosion resistance of the part where the plating layer is missing (particularly the welded part) is maintained. Can be realized.

It is a width direction sectional view showing typically the structure of the plating welding section steel concerning the embodiment of the present invention. It is the width direction sectional view which expanded and showed the structure of the welding part of plating welding section steel in the embodiment. It is the cross-sectional view which expanded and showed the structure of the end surface of the plating welded shaped steel which concerns on the same embodiment. It is an electron micrograph of plating welding H-section steel which shows the layer structure of plating welding H-section steel. It is an electron micrograph of plating welding H-section steel which shows the layer structure of plating welding H-section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel. It is the cross-sectional view of the width direction which showed typically the lamination pattern of the test piece of plating welding H section steel.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(About galvanized welded steel)
Hereinafter, with reference to FIGS. 1 to 3, a detailed description will be given of a plated welded lightweight steel (hereinafter, also simply referred to as “plated welded steel”) according to an embodiment of the present invention.
FIG. 1 is a cross-sectional view schematically showing the structure of the plated welded steel shape according to the present embodiment. FIG. 2 is a cross-sectional view in the width direction in which the structure of the welded portion of the plated welded steel is enlarged and shown in the present embodiment. FIG. 3 is a cross-sectional view in the width direction in which the structure of the end surface of the plated welded steel according to the present embodiment is enlarged and shown.

<Overall structure of galvanized welded steel>
First, the overall structure of the plated welded steel shape 1 according to the present embodiment will be described in detail with reference to FIG.
The plated welded lightweight steel 1 according to the present embodiment is a plated welded H-section steel. The galvanized lightweight steel 1 includes, for example, a coil formed by winding a zinc-based plated steel strip, which is unwound and slit into a predetermined width to form a flange steel strip, and a coil formed by winding a zinc-based plated steel strip. It is manufactured by continuously welding by means of high-frequency resistance welding or high-frequency induction welding in a state where the steel strip for the web that has been returned is brought into contact with the steel strip.

The galvanized welded steel 1 produced in this manner has a pair of flanges 3 provided so as to face each other and a web 5 connecting the two flanges 3, as schematically shown in FIG. 1. It consists of

In the plated welded steel shape 1 according to the present embodiment, the width and the thickness of the flange 3 or the web 5 are not particularly limited. For example, the plated welded steel 1 is a typical plated welded H-section steel,
Flange 3: Width 75 mm to 125 mm, thickness 3.2 mm to 6.0 mm
Web 5: height 100 mm to 300 mm, thickness 3.2 mm to 4.5 mm
It is about the size.

In the galvanized steel section 1 according to the present embodiment, as described above, the zinc-based galvanized steel strip to be the flange 3 and the zinc-based galvanized steel strip to be the web 5 are connected by a welding process. Therefore, a welded portion 7 is formed at the connecting portion between the flange 3 and the web 5, as schematically shown in FIG.

In the galvanized welded steel 1 according to the present embodiment, since a zinc-based galvanized steel strip is used as a raw material, the surface layer of the steel sheet (hereinafter, also simply referred to as “base material steel sheet”) 11 serving as a base material has zinc. The system plating layer 13 and the chemical conversion coating 101 are formed. However, due to the heat generated by the above-mentioned welding process, the zinc-based plating layer 13 and the chemical conversion coating 101 are not present in the welded portion 7. Further, the zinc-based plating layer 13 and the chemical conversion coating 101 are often not present on the end surface 9 of the flange 3 as well.

Therefore, in the galvanized welded steel 1 according to the present embodiment, a portion which is a connecting portion between the flange 3 and the web 5 and a region in the vicinity thereof, and in which the zinc-based plating layer 13 and the chemical conversion coating 101 do not exist, , Can be considered as the weld 7. Further, since the zinc-based plated steel strip to be the flange 3 and the zinc-based plated steel strip to be the web 5 are welded while being pressed together, a bead 15 is generated immediately after welding. In the welded welded steel shape 1 according to the present embodiment, the forming process is performed by crushing the bead 15 with a roller or the like after welding, and the bead 15 is seen from the side as schematically shown in FIG. The shape is a substantially triangular shape. Therefore, in the plated welded steel shape 1 according to the present embodiment, a portion where the bead 15 is present in a substantially triangular shape can be considered as the welded portion 7.

The bead 15 is mainly composed of a component of the base steel plate 11 and a scale containing iron oxide as a main component, and may contain a component of the zinc-based plating layer 13 and the like.

Here, the base material steel plate 11 is not particularly limited, and a steel plate that is usually used as a base plate of a zinc-based plated steel plate can be appropriately used. The production method of this original plate, the material, etc. are not particularly limited, and those produced through the steps of normal steel billet manufacturing process such as hot rolling, pickling, cold rolling, annealing, temper rolling, etc. You can use it.

Also, the type of the zinc-based plating layer 13 is not particularly limited, and a known zinc-based plating treatment such as hot dip galvanizing or electrogalvanizing is used to make the zinc-based plating layer according to the present embodiment. It is possible to form 13. The plating component is also not particularly limited, and may be pure zinc plating or zinc alloy-based plating. Examples of the components of the zinc alloy-based plating include, in mass%, Zn-11%Al-3%Mg-0.2%Si, Zn-6%Al-3%Mg, Zn-55%Al, or Zn. -1 to 3% Al -1 to 3% Mg and the like can be mentioned, but the invention is not limited thereto.

In the galvanized welded steel 1 according to the present embodiment, by using the zinc-based plated steel sheet on which the zinc-based plating layer 13 is formed as a raw material, the sacrificial anticorrosive ability of zinc improves the corrosion resistance of the entire shaped steel. It becomes possible to guarantee.

The thickness and the amount of the zinc-based plating layer 13 are not particularly limited, and may be appropriately set according to the required performance, cost, etc. of the galvanized welded steel 1. For example, the zinc-based plating layer 13 may be formed on the surface of the base steel sheet 11 with a thickness of 1 μm to 80 μm per side, and more preferably with a thickness of about 20 μm per side. If the thickness of the zinc-based plating layer 13 is less than 1 μm, it is difficult to realize the sacrificial anticorrosive ability of zinc, which is not preferable. Further, if the thickness of the zinc-based plating layer 13 exceeds 80 μm, the workability of the zinc-based plating layer decreases, which is not preferable. Further, the adhesion amount of the zinc-based plating layer 13, a metal Zn amount per surface, for ^example, it is preferable to ^{7g / m 2 ~560g / m 2} .

A chemical conversion treatment film (first film) 101 is formed on the zinc-based plating layer 13. The chemical conversion coating 101 protects the zinc-based plating layer 13 from electrolytes such as water, air, and salt that are present in the ambient atmosphere, and prevents corrosion of the zinc-based plating layer 13. This improves the corrosion resistance of the zinc-based plating layer 13.

However, like the zinc-based plating layer 13, the chemical conversion coating 101 is not present in the welded portion 7 due to the heat generated by the above-mentioned welding treatment. Further, the chemical conversion coating 101 is often not present on the end surface 9 of the flange 3 as well.
The detailed components of the chemical conversion coating 101 will be described later.

<About the structure of the welded part>
Next, the structure of the welded portion 7 of the plated welded steel shape 1 according to the present embodiment will be specifically described with reference to FIG. 2.

As previously described, in the galvanized steel section 1 according to this embodiment, when the flange 3 and the web 5 are connected by welding, the zinc-based plating layer 13 formed on the surface of the base steel sheet 11 and The chemical conversion coating 101 is removed. Therefore, the corrosion resistance of the welded portion 7 becomes lower than that of the portion where the zinc-based plating layer 13 is formed.

Therefore, the present inventors diligently studied a method for performing the zinc rich coating on the welded portion 7 without performing the blast treatment as the base material conditioning treatment prior to the zinc rich coating treatment. As a result, they have found that it is preferable to dispose not only the bead 15 but also the zinc-rich coating film up to the chemical conversion treatment film 101 around the bead 15 in order to sufficiently protect the bead 15. On the other hand, the present inventors faced the problem that the zinc-rich coating film was difficult to adhere to not only the bead 15 of the welded portion 7 but also the chemical conversion treatment coating 101. Then, the inventors of the present invention provided an organic coating layer (third coating, organic zinc-rich coating) 105 containing zinc particles with a bead 15 and a resin layer (second coating) 103 containing a resin material interposed therebetween. By disposing on the chemical conversion treatment film 101, the adhesion of the organic coating layer 105 to the beads 15 and the chemical conversion treatment film 101 can be made excellent, and the corrosion resistance of the beads 15 can be improved. Found.

Therefore, in the welded portion 7 of the plated welded H-section steel 1 according to the present embodiment, as shown in FIG. 2, the cross-sectional structure has the base material steel plate 11 that is the base, and Fe on the base material steel plate 11 is present. There is a bead 15 containing as a main component. Then, the resin layer 103 is arranged so as to cover the bead 15 and a part of the chemical conversion treatment film 101 existing around the bead 15, and the organic coating layer 105 is formed on the resin layer 103. Has been done. The organic coating layer 105 is arranged so as to cover the beads 15.

With the above-described layer structure, even in the welded portion 7 where the zinc-based plating layer 13 does not exist, the bead 15 is provided due to the sacrificial anticorrosive ability of zinc contained in the organic coating layer 105 in a large amount. Corrosion resistance of will be secured. Further, by disposing the organic coating layer 105 on the bead 15 and the chemical conversion coating 101 via the resin layer 103, the bead 15 of the organic coating layer 105 and the chemical conversion coating 101 on the resin layer 103 are provided. It is possible to obtain excellent adhesion to the.

<About the structure of the end face>
Next, the structure of the end surface 9 of the plated welded steel shape 1 according to this embodiment will be specifically described with reference to FIG. 3.
As described above, in the galvanized welded steel 1 according to the present embodiment, due to the manufacturing process, the zinc-based plating layer 13 does not exist on the end face 9 and the base steel plate 11 is exposed. There are many. Therefore, the corrosion resistance of the end face 9 becomes lower than that of the portion where the zinc-based plating layer 13 is formed.

Therefore, as shown in FIG. 3, the end surface 9 also covers the end surface 9 of the base material steel plate 11 and further covers a part of the chemical conversion treatment film 101 existing around the end surface of the base material steel plate 11. The resin layer 103 is disposed on the resin layer 103, and the organic coating layer 105 is formed on the resin layer 103. The organic coating layer 105 is arranged so as to cover the end surface 9.

With the above-described layer structure, even when the zinc-based plating layer 13 is not present on the end surface 9, the end surface is protected by the sacrificial anticorrosive ability of a large amount of zinc contained in the organic coating layer 105. Corrosion resistance of the base material steel plate 11 in 9 will be ensured. Further, by arranging the organic coating film layer 105 on the end surface 9 via the resin layer 103, the adhesion to the end surface 9 of the organic coating film layer 105 and the chemical conversion treatment film 101 via the resin layer 103 is excellent. It can be

The overall configuration of the plated welded steel shape 1 according to the present embodiment has been described above. Next, the chemical conversion treatment film 101, the resin layer 103, and the organic coating film layer 105 arranged on the above-mentioned plated welded steel 1 will be described in detail.

<Chemical conversion coating 101>
In this embodiment, the chemical conversion coating 101 is a composite coating containing a zirconium (Zr) element and an organic acid. The chemical conversion treatment film 101 preferably contains, as components, a vanadium (V) element, a phosphorus (P) element, and a cobalt (Co) element in addition to the zirconium element and the organic acid.

Such a chemical conversion treatment film 101 is a composite film having a dense three-dimensional structure, excellent barrier properties, and improved corrosion resistance. In such a composite coating film, a dense three-dimensional network structure is formed mainly by Zr-O by the coordination of an organic acid and a metal ion by complex formation. It is considered that vanadium, organic acid, phosphorus, and cobalt are mixed between the three-dimensional network structure, and zinc released by etching the plating surface is further incorporated. In the above three-dimensional structure of Zr-O, some Zr may be replaced with another element. Further, by etching the plating surface with an organic acid when forming the chemical conversion coating 101, the adhesion at the interface between the coating and the plating surface is increased, and the corrosion resistance and the coating adhesion are improved.

As described above, the chemical conversion coating 101 contains an organic acid. The organic acid is not particularly limited, for example, glycolic acid, malic acid, tartaric acid, oxalic acid, citric acid, ascorbic acid, lactic acid, dehydrobenzoic acid, dehydroascorbic acid, gallic acid, tannic acid, phytic acid. And so on.

In the chemical conversion treatment film 101, the organic acid is preferably present in an amount of 10 to 90 parts by mass with respect to 100 parts by mass of Zr. As a result, the chemical conversion coating 101 can have sufficient corrosion resistance and alkali resistance. The content of the organic acid in the chemical conversion coating 101 is preferably 10 to 70 parts by mass, more preferably 10 to 50 parts by mass, and particularly preferably 15 to 30 parts by mass with respect to 100 parts by mass of Zr.

In the chemical conversion coating 101, the element V is preferably present in an amount of 10 to 45 parts by mass with respect to 100 parts by mass of Zr. As a result, the chemical conversion coating 101 can have sufficient corrosion resistance, alkali resistance, and blackening resistance. The amount of V in the chemical conversion treatment film 101 is preferably 15 to 30 parts by mass, and more preferably 20 to 25 parts by mass with respect to 100 parts by mass of Zr.

Further, in the chemical conversion coating 101, the elemental P is preferably present in an amount of 5 to 100 parts by mass with respect to 100 parts by mass of Zr. As a result, the chemical conversion coating 101 can have sufficient corrosion resistance, alkali resistance, and blackening resistance. The amount of P in the chemical conversion coating 101 is preferably 10 to 70 parts by mass, more preferably 10 to 40 parts by mass, and particularly preferably 12 to 20 parts by mass with respect to 100 parts by mass of Zr.

In the chemical conversion treatment film 101, 0.1 to 20 parts by mass of elemental Co is preferably present with respect to 100 parts by mass of Zr. As a result, the chemical conversion coating 101 can have sufficient corrosion resistance, alkali resistance, and blackening resistance. In particular, it is considered that the effect of cobalt is to promote the inactivation of the surface of the plated steel material at the time of film formation and to protect it from external factors such as water and oxygen. The amount of Co in the chemical conversion coating 101 is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and particularly preferably 0.8 to 1.5 parts by mass with respect to 100 parts by mass of Zr. It is a department.

The chemical conversion coating 101 is preferably 10 to 90 parts by mass of an organic acid, 10 to 45 parts by mass of V element, 5 to 100 parts by mass of P element, and 0.1% of Co element with respect to 100 parts by mass of Zr element. It is contained in a ratio of 20 parts by mass. The chemical conversion coating 101 may include components other than the components described above.

The thickness and the adhesion amount of the chemical conversion coating 101 are not particularly limited, and may be appropriately set according to the required performance of the welded steel section 1 and the cost. For example, the adhesion amount of chemical conversion coating 101, per side, for ^{example, 0.01g / m 2 ~2.0g / m} 2, preferably to a 0.05g ^{/ m 2} ~1.0g ^/ m 2 ..

<Regarding the resin layer 103>
Next, the resin layer 103 formed on the welded portion 7 and the end surface 9 of the plated welded steel shape 1 according to this embodiment will be described in detail.

The resin layer 103 according to the present embodiment is a base coating film formed to ensure adhesion between the steel component located below the resin layer 103 and the organic coating film layer 105 located above. It is a layer.

As the resin forming the resin layer 103, for example, a resin containing an epoxy resin, a urethane resin, an acrylic resin and/or a polyester resin is preferably used. As described above, by using the resin having particularly excellent adhesion to the steel located in the lower layer, the adhesion between the organic coating layer 105 and the steel component can be further improved. An epoxy resin is particularly preferable as the resin forming the resin layer 103.

Specific examples of the epoxy-based resin include, for example, EPICLON (registered trademark) 840 and 850 series manufactured by DIC, which is a bisphenol A type epoxy resin. A low viscosity is advantageous for applying a thin film, and EXA-850CRP can be exemplified as such a low-viscosity epoxy resin.

Specific examples of the acrylic resin include DIC's Acridic (registered trademark) A-1371 and A-1381 series, which are acrylic resins for normal temperature and forced drying.

Specific examples of urethane-based resins include moisture-curable, lacquer-type, and oil-modified urethane resins. Examples of such urethane-based resin include urethane resin BURNOCK (registered trademark) series manufactured by DIC.

Specific examples of polyester resins include unsaturated polyester resins and alkyd resins. Examples of paints using such polyester resins include Inovax (registered trademark) PCM series manufactured by Shinto Paint Co., Ltd.

The thickness of the resin layer 103 formed by using at least one kind of the above resin or paint is not particularly limited, but is, for example, 3 to 30 μm, preferably the lower limit is 5 μm, the upper limit is 20 μm, and more preferably the lower limit is 8 μm. can do. In the case of the above range, the adhesion between the steel component or the chemical conversion coating 101 and the organic coating layer 105 located in the lower layer, and the corrosion resistance until the organic coating layer 105 is formed are sufficient. Can be secured. On the other hand, when the thickness of the resin layer 103 is within the above range, the time required for coating and drying can be relatively shortened and the workability in forming the resin layer 103 becomes good. The above-mentioned thickness is realized on a flat plate when the resin liquid for forming the resin layer 103 is coated on the flat plate by using the same film forming conditions as when forming the resin layer 103. It is the thickness.

Further, as the resin for forming the resin layer 103, by using a resin compatible with the binder resin of the paint used for forming the organic coating layer 105, the resin layer 103 and the organic system It is possible to further improve the adhesiveness with the coating layer 105. Further, as a resin for forming the resin layer 103, a binder resin of a paint used for forming the organic coating layer 105 may be used.

Therefore, as the resin for forming the resin layer 103, by using a resin that has good adhesiveness with the steel component and is compatible with the binder resin of the organic coating layer 105, It is possible to further improve the adhesion of the system coating layer 105.

Further, the resin layer 103 according to the present embodiment is arranged not only on the bead 15 and the steel material 11 on the end face 9 but also on the chemical conversion treatment film 101, as schematically shown in FIGS. 1 to 3. When the resin layer 103 is arranged only on the bead 15 and the steel material 11 on the end face 9, moisture, oxygen, and the like in the ambient atmosphere may contact the steel material 11 on the bead 15 and the end face 9 near the edge of the resin layer 103. However, such contact can be prevented by disposing the resin layer 103 also on the chemical conversion treatment film 101 as described above. Although it is possible to dispose the organic coating film layer 105 directly on the chemical conversion treatment film 101, by disposing the resin layer 103 between them, the conversion coating film 101 and the organic coating film layer 105 are separated from each other. The adhesiveness between them can be made even more excellent.

<Regarding the organic coating layer 105>
Subsequently, the organic coating film layer 105 formed on the welded portion 7 and the end surface 9 of the plated welded steel shape 1 according to the present embodiment will be described in detail.

An organic coating film layer (organic zinc rich coating film layer) 105 containing a predetermined amount of zinc powder is formed on the bead 15 (preferably above the resin layer 103 as described above). To be done. By forming such an organic coating layer 105, it is possible to improve the corrosion resistance even in a portion where the zinc plating layer 13 does not exist, such as the welded portion 7 and the end surface 9. In the present invention, the organic coating layer may cover the bead (welding bead) and at least a part of the resin layer, but from the viewpoint of further improving the corrosion resistance, the zinc-based plating layer. It is preferable to arrange so as to cover all the regions where no. In the present embodiment, the organic coating film layer 105 is formed so as to cover the bead 15 and all the missing portions of the zinc plating layer of the end face 9 with the resin layer 103 interposed therebetween.

In addition, as shown in FIGS. 1 to 3, the organic coating layer 105 normally covers all of the bead 15 and the missing portion of the zinc plating layer of the end face 9 via the resin layer 103, but the zinc of the bead 15 and the end face 9 is not covered. A very small portion of the organic coating layer 105 on the plating layer defective portion may be defective. However, even in such a case, the organic coating film layer 105 covers the area of the bead 15 and the galvanized layer deficient portion of the end surface 9 of preferably 95%, more preferably 98%, particularly preferably 99% or more. Is formed as.

The organic coating layer 105 is formed so as not to come into direct contact with the chemical conversion coating 101. By being formed in this manner, the coating film adhesion of the organic coating film layer 105 can be made more excellent. In addition, the invention is not limited to the illustrated embodiment, and in the present invention, a part of the organic coating film layer may be in contact with the chemical conversion coating.

The organic coating layer 105 is formed using an organic zinc rich paint containing at least a predetermined amount of zinc powder and an organic binder component. Zinc-rich paints are roughly classified into water-based zinc-rich paints and solvent-based zinc-rich paints depending on the solvent used, and organic zinc-rich paints and inorganic zinc-rich paints depending on the type of binder component used. It is roughly divided into In the galvanized welded steel 1 according to the present embodiment, it is preferable to use a solvent-based organic zinc-rich paint as the zinc-rich paint for forming the organic coating layer 105.

The organic zinc-rich paint used to form the organic coating layer 105 contains 60% by mass or more of zinc powder as a main component with respect to the entire nonvolatile components (solid content). preferable. Here, the content of the zinc powder contained in the organic zinc rich paint is the content of the zinc powder contained in the organic coating layer 105. By containing the zinc powder in the above content, the organic coating layer 105 can realize excellent sacrificial anticorrosion ability. The content of the zinc powder contained in the organic zinc rich paint is more preferably 80% by mass to 99% by mass.

In addition, such an organic zinc-rich paint may further contain metals, alloys, compounds and the like containing elements such as aluminum, magnesium, silicon, iron and nickel as long as zinc powder is contained in an amount of 60% by mass or more. It may be contained. The content of these elements is not particularly limited, but is, for example, 5% by mass to 40% by mass, preferably 5% by mass to 20% by mass.

The shape of the zinc powder contained in the organic coating layer 105 is not particularly limited, and may be any shape such as spherical, rod-shaped, lump-shaped, or needle-shaped, and may be blended. The average particle size of the zinc powder contained in the organic coating layer 105 is preferably 0.1 μm to 100 μm, more preferably 0.1 μm to 50 μm. The average particle size of the zinc powder can be measured using a known method such as a dynamic light scattering method, a guided diffraction grating method, a laser diffraction/scattering method.

As the binder component contained in the zinc rich paint, it is possible to use the organic binder component as described above.

The organic binder component is not particularly limited, but may be, for example, a resin containing the above-described epoxy resin, acrylic resin, urethane resin and/or polyester resin. A specific example is as described above.

It should be noted that, to the organic zinc-rich paint used for forming the organic coating film layer 105, an ordinary extender pigment, a rust preventive pigment, a coloring pigment, etc. are added as necessary to such an extent that the denseness of the coating film is not impaired. You may. Examples of extender pigments include silica powder, barium sulfate, calcium carbonate, talc, kaolin, clay and silica balloons, and examples of the rust preventive pigments and coloring pigments include titanium oxide, iron phosphide and mica. Iron oxide, lead cyanamide, zinc chromate, zinc phosphate, calcium phosphate, barium metaborate, zinc molybdate, aluminum molybdate, red iron oxide, cyanine color pigment, carbon black, rutile powder, zircon powder and the like.

Further, the organic zinc-rich paint used for forming the organic coating layer 105 may further contain a usual anti-settling agent, anti-sagging agent, wetting agent, reaction accelerator, adhesion-imparting agent, etc., if necessary. A paint additive may be appropriately added.

The thickness of the organic coating layer 105 formed by using the organic zinc rich paint as described above is approximately twice the thickness of the zinc plating layer 13 formed on the base steel plate 11. Is preferred. By setting the thickness of the organic coating layer 105 to be about twice the thickness of the zinc plating layer 13, the organic coating layer 105 achieves substantially the same corrosion resistance as the zinc plating layer 13. Is possible.

More specifically, the thickness of the organic coating layer 105 is preferably 5 μm to 200 μm. When the thickness of the organic coating layer 105 is less than 5 μm, it may be difficult to realize a sufficient sacrificial anticorrosive ability. Further, when the thickness of the organic coating layer 105 is more than 200 μm, the drying property of the coating film is poor and dripping may occur, which is not preferable. The thickness of the organic coating layer 105 is more preferably 10 μm to 150 μm, further preferably 20 μm to 100 μm.

Also, when representing the thickness of the organic coating layer 105 as described above in adhesion amount, the adhesion amount, a metal Zn amount conversion ^is preferably ^{18g / m 2 ~700g / m 2} , 35g / more preferably ^{m 2} ~700g / m ^2, and still more preferably from ^{70g / m 2 ~700g / m 2} .

The organic coating layer 105 according to the present embodiment is arranged not only on the bead 15 and the steel material 11 on the end face 9 but also on the chemical conversion coating 101, as schematically shown in FIGS. 1 to 3. ing. Thereby, the bead 15 and the steel material 11 on the end surface 9 can be surely covered with the organic coating layer 105, and the corrosion resistance of the portion where the zinc-based plating layer 13 is missing can be made sufficiently high. The adhesiveness between the organic coating layer 105 and the chemical conversion coating 101 is sufficient due to the above-mentioned resin layer 103 existing between them.

The configuration of the plated welded steel shape 1 according to the present embodiment has been described above with reference to FIGS. 1 to 3.

A coating film containing a bright pigment can be arranged on the organic coating layer 105 of the plated welded steel 1 (not shown). Usually, since the organic coating layer 105 has a low gloss, the repair coating portion may be conspicuous and the designability may be impaired depending on the application. However, by disposing a coating film containing a bright pigment on the organic coating layer 105, it is possible to finish the metallic appearance similar to that of a sound part where the plating layer is not missing.

Such a glittering pigment is not particularly limited, but examples thereof include metal pieces such as aluminum, glass flakes, silica flakes, effect pigments such as aluminum oxide flakes, and pearl pigments. Of these, when a metal piece such as aluminum is used as the bright pigment, the presence of the organic coating layer 105 can be made less conspicuous.
Further, the coating film containing the above-described bright pigment can be formed, for example, by applying a coating material containing a resin material such as an epoxy resin by spraying or the like.

A coating film containing such a bright pigment can be formed not only on the organic coating film layer 105 described above, but also on the entire surface of the plated welded steel 1.

Moreover, although the plated welded section steel 1 according to the present embodiment has been described as being the plated welded H section steel, the present invention is not limited to this. For example, the galvanized welded steel according to the present invention may be, for example, welded T-section steel, welded channel steel, welded column or welded profile steel.

<About manufacturing method of galvanized steel section>
Next, a method for manufacturing the plated welded steel will be described.
In the method for producing a galvanized welded steel according to the present embodiment, a web made of a galvanized steel sheet, a galvanized steel sheet, a flange welded to the web, and a welded portion of the web and the flange. At least a part of the weld bead and the first coating for a welded welded section steel comprising a weld bead to be formed, and a first coating formed on the web and the flange and containing zirconium and an organic acid. Forming a second coating film containing a resin material, which covers at least a part of (1st step),
Zinc, which cures the plated welded steel having the second coating formed thereon for at least 4 hours or more (second step), covers the welding beads, and covers at least a part of the second coating. An organic third coating containing particles is formed (third step). Specific examples of each step will be described below.

First, in the first step, first, the web 5 and the flange 3, the bead (weld bead) 15 located at the welded portion of the web and the flange, and the chemical conversion treatment film (first film) on the web 5 and the flange 3 are formed. ) 101 is arranged to prepare the plated welded steel shape 1. As described above, the galvanized welded steel 1 includes, for example, a coil formed by winding a zinc-based plated steel strip, which is rewound and slit into a predetermined width to form a steel strip for web, and a zinc-based plated steel strip. It is manufactured by continuously welding, by high-frequency resistance welding, high-frequency induction welding, etc., in a state where the coil and the steel strip for flanges that have been rewound are brought into contact with each other.

The chemical conversion coating 101 can be previously formed on a zinc-based plated steel strip which is a part of the galvanized welded steel 1. The chemical conversion treatment film 101 is not particularly limited, but can be produced, for example, by applying an aqueous solution containing each component of the above-described chemical conversion treatment film 101 on the zinc-based plating layer 13 and heating and drying to form a film. .. Such an aqueous solution is, for example, a basic zirconium compound, a vanadyl (VO 2 ⁺ )-containing compound, a phosphoric acid compound, a cobalt compound, and an organic compound in an amount that supplies Zr, V, P, Co elements and an organic acid in the above-described ratio. It can include acids or organic acid salts.

Next, the bead 15 of the plated welded steel 1 and the resin layer (second film) 103 that covers the first coating 101 around the bead 15 are formed. The method for forming the resin layer 103 is not particularly limited, and the resin used for forming the resin layer 103 is dispersed in an appropriate solvent, and then the resin liquid is attached to the surfaces of the welded portion 7 and the end surface 9 in a predetermined manner. The amount of the resin liquid may be sprayed so that the amount of the resin liquid is sprayed, the amount of the resin liquid may be sprayed, and then the amount of the resin liquid may be controlled by spraying a roll or a gas so that the amount of the resin liquid is sprayed to a predetermined amount.

Also, the drying method and the precure method are not limited to specific methods as long as the dispersion medium can be volatilized. For example, heating at a temperature of about 80° C. for about 60 seconds is possible. Such known processing may be performed.

Further, when the resin layer 103 is formed on the welded portion 7, the resin liquid for forming the resin layer 103 permeates the scale mainly existing on the surface of the bead 15 and the bead 15 itself. It is preferable to proceed. As the resin layer 103 penetrates into the beads 15, the adhesiveness of the organic coating film layer 105 can be further improved. For that purpose, it is preferable that the viscosity and wettability of the resin used for forming the resin layer 103 satisfy predetermined conditions. Specifically, the viscosity of the resin liquid used to form the resin layer 103 is preferably 3.0 Pa·s or less, and the wettability is preferably a contact angle of 90 degrees or less.

Next, in the second step, the plated welded steel 1 on which the resin layer 103 is formed is cured for at least 4 hours or longer. By performing curing after forming the resin layer 103 in this way, the resin material in the resin layer 103 can be sufficiently dried or cured. As a result, when the plated welded steel 1 is handled, the resin layer 103 is sufficiently prevented from peeling off or from blocking with the resin layer 103 of another adjacent plated welded steel 1. When blocking occurs, the peeling strength of the resin layer 103 is reduced, or traces of what is the object of blocking are formed on the resin layer 103. In such a case, there is a concern that the peeling strength of the resin layer 103 may be reduced and the corrosion resistance may be reduced, or the design may be reduced due to the formation of traces. However, in the present embodiment, such a problem is sufficiently prevented by curing for a predetermined time.

The curing time in this step is not particularly limited as long as it is 4 hours or more as described above, but is preferably 6 hours or more, more preferably 12 hours or more. Thereby, the resin material in the resin layer 103 can be sufficiently dried and hardened, and the contact of moisture, oxygen, etc. with the plated welded steel 1 in the ambient atmosphere due to curing should be sufficiently small. You can

The specific curing method is not particularly limited. For example, after the resin layer 103 is formed, the resin layer 103 is kept in a state where it does not come into contact with other members as much as possible, and left in an ambient atmosphere to perform curing. be able to.

Next, in the third step, the organic coating layer 105 that covers the beads 15 and at least part of the resin layer 103 is formed. In addition, in this embodiment, the organic coating layer 105 is formed so as to cover the bead 15 and the chemical conversion treatment film 101 on the peripheral portion thereof via the resin layer 103.

The method for forming the organic coating film layer 105 is not particularly limited, and the surface of the resin layer 103 at the welded portion 7 or the end surface 9 is spray-coated with the above organic zinc rich paint. It can be formed by Further, the amount of adhesion may be controlled by a roll or gas spraying so that the predetermined amount of adhesion may be obtained, or the organic zinc rich paint may be applied by a roll coater or the like. After applying the organic zinc rich paint, the organic coating film layer 105 is formed by drying.

As described above, the plated welded steel shape 1 according to the present embodiment is manufactured. Such a galvanized welded steel 1 has sufficiently high corrosion resistance due to the chemical conversion coating 101, the resin layer 103 and the organic coating layer 105. Further, since the organic coating layer 105 is formed via the resin layer 103, it has excellent adhesion to the plated welded steel 1. Further, in the method for manufacturing the plated welded steel 1 according to this embodiment, since the resin layer 103 is cured in the second step, the adhesion of the resin layer 103 to the beads 5 and the steel material 11 and the chemical conversion coating 101 is improved. It is high enough.

<About measurement methods>
Next, various measurement methods for the chemical conversion treatment film 101 of the galvanized welded steel 1 according to the present embodiment, and the resin layer 103 and the organic coating layer 105 on the welded portion 7 and the end surface 9 will be briefly described.

The presence of the resin layer 103 and the organic coating layer 105 formed on the welded portion 7 and the end surface 9 of the plated welded steel 1 according to the present embodiment scans the cross section of the sample cut out from the produced plated welded steel. It can be confirmed by observing with a scanning electron microscope (SEM). Further, by observing the cross section with the SEM, it can also be confirmed that the blasting treatment is not performed as the substrate adjustment for forming the organic coating film layer 105. Further, by observing the cross section with the SEM, it is possible to measure the thickness and the range of existence of the resin layer 103 and the organic coating layer 105.

In some cases, the contrast between the bead 15 (or the scale forming the bead 15) and the resin layer 103 or the contrast between the resin layer 103 and the organic coating layer 105 is not clear, It is also possible that the existence of the layer 103 cannot be confirmed. However, for the sample in which the resin layer 103 is known to be formed, the resin layer 103 is indirectly measured by measuring and evaluating the distance between the zinc particles contained in the organic coating layer 105 and the bead 15. It is possible to confirm the existence of.

The existence of the chemical conversion coating 101 formed on the web 5 and the flange 3 of the plated welded steel 1 according to the present embodiment is determined by elemental analysis using an electron probe micro analyzer (EPMA) attached to the SEM. You can check. Specifically, the cross section of the sample cut out from the plated welded shaped steel manufactured in the same manner as above is observed by SEM, and elemental analysis of chemical conversion treatment component elements is performed between the zinc-based plating layer 13 and the resin layer 103. The presence of the chemical conversion coating 101 can be confirmed by.

The amount of the chemical conversion coating 101 formed on the web 5 and the flange 3 of the galvanized welded steel 1 according to this embodiment can be measured as, for example, the amount of weight reduction. Specifically, a non-painted portion where the resin layer 103 is not formed is cut out and immersed in a chromic acid solution or the like to dissolve the chemical conversion treatment film 101, and the weight difference between before and after is measured to determine the adhesion amount of the chemical conversion treatment film 101. To do.

Further, if a sample in which the adhesion amount of the chemical conversion treatment film 101 is changed is prepared and a calibration curve sample of a specific element of the chemical conversion treatment component is prepared, it is possible to quantify the adhesion amount of the chemical conversion treatment by analysis such as fluorescent X-ray. .. Specifically, a chromic acid solution or the like in which the chemical conversion treatment film 101 is dissolved is subjected to inductively coupled high frequency plasma emission spectrometry (ICP-AES) and inductively coupled high frequency plasma mass spectrometry (inductively coupled plasma mass spectrometry). Plasma-Mass Spectro-metry (ICP-MS). Using this quantitative value and the weight value, a calibration curve sample is prepared. By comparing and analyzing the prepared calibration curve sample and the specific element of the chemical conversion treatment film 101 cut out from the welded steel 1, the adhesion amount of the chemical conversion treatment film 101 can be measured by X-ray analysis.

Specific confirmation methods include, for example, the following methods.
Here, as a more specific example, a film is formed on a welded portion of a plated welded H-section steel, which is formed by joining a web made of a zinc-based plated steel strip and a flange, to a welded portion having a scale without blasting. An epoxy resin containing scaly aluminum metal pieces was coated so that the thickness was about 10 μm. Then, an organic zinc rich coating containing granular zinc powder was applied onto the epoxy resin. The zinc-based plated steel strip used had a chemical conversion treatment film formed by chemical conversion treatment.

The chemical conversion treatment film is formed by applying an aqueous solution containing a basic zirconium compound, a vanadyl (VO 2 ⁺ )-containing compound, a phosphoric acid compound, a cobalt compound and an organic acid salt to both sides of a zinc-based plated steel strip by roll coating and drying. Was formed by.

A sample including a weld bead portion was cut out from this welded H-section steel. In order to protect the surface of the cut-out sample, the surface was protected with a quick-drying paint and then embedded in an embedding resin. After the embedding resin solidified, the cross section was buffed. After that, C vapor deposition was performed to prevent charge-up. The results of SEM observation are shown in FIG. 4A below. The magnification of the SEM photograph of FIG. 4A is 20 times.

As is clear from FIG. 4A, a thin resin layer was observed in the upper layer of the weld bead portion of the welded H-section steel, and the film thickness of the resin layer could be evaluated. Further, a zinc-rich coating layer was observed as an organic coating layer on the resin layer. Further, it was confirmed that the epoxy resin coating applied for protection when the sample was prepared was formed on the zinc rich coating layer.

Further, FIG. 4B shows the result of SEM observation of the center of the weld bead portion at a magnification of 500 times.
As is clear from FIG. 4B, a thin scale was observed in the upper layer of the weld bead portion of the welded H-section steel, and a resin layer was observed in the upper layer of the scale, and the film thickness of the resin layer was evaluated. It was possible. As described above, the presence of the resin layer applied before the zinc rich coating was confirmed, the presence of scale was also confirmed, and it was also confirmed that the blast treatment was not performed.

Further, from the element mapping image, it was confirmed that P derived from the phosphoric acid component contained in the chemical conversion treatment was present on Zn derived from the plating layer. Thus, it was confirmed that the chemical conversion coating, the resin layer and the zinc rich coating layer were arranged in this order on the steel at the peripheral portion of the bead.

Further, also for the end surface 9 of the plated welded H-section steel 1 according to the present embodiment, a sample for observation is prepared in the same manner as above, and the cross section thereof is observed by SEM, whereby the chemical conversion treatment film 101, the resin layer 103, and It is possible to measure the existence range and thickness of the organic coating layer 105.

Heretofore, various measuring methods for the chemical conversion coating 101, the resin layer 103, and the organic coating layer 105 on the welded portion 7 and the end surface 9 of the plated welded H-section steel 1 according to the present embodiment have been briefly described.

Hereinafter, the galvanized welded steel and the method for manufacturing the galvanized welded steel according to the present invention will be specifically described with reference to Examples. In addition, the examples shown below are merely examples of the method for producing a plated welded section steel and a plated welded section steel according to the present invention, and the method for producing a plated welded section steel and a plated welded section steel according to the present invention are It is not limited to the following example.

In the following, a plated welded H-section steel manufactured by using a general zinc-based plated steel strip is used, and the following treatment is applied to the welded portion between the web and the flange of such a plated welded H-section steel. Carried out. The component of the zinc alloy-based plating layer formed on the used zinc-based plated steel strip is Zn-11%Al-3%Mg-0.2%Si in mass %. The amount of the zinc alloy-based plating layer on the zinc-based plated steel strip used was 140 g/m ² per side. In addition, it was confirmed that the welded portion of the plated welded H-section steel used below had a bead composed of a component of the base steel sheet and a scale containing iron oxide as a main component.

Further, a chemical conversion treatment film is formed on the used zinc-based plated steel strip. The chemical conversion treatment film is formed by applying an aqueous solution containing a basic zirconium compound, a vanadyl (VO 2 ⁺ )-containing compound, a phosphoric acid compound, a cobalt compound and an organic acid salt to both sides of a zinc-based plated steel strip by roll coating and drying. Was formed by. The amount of the chemical conversion coating deposited was 100 mg/m ² .

Here, in the welded portion between the web and the flange of the plating welded H-section steel, the plating and the chemical conversion treatment coating disappear and the scale is formed by welding.

The plating component in the plating layer formed on the plated welded H-section steel used in the examples was Zn-11%Al-3%Mg-0.2%Si as described above, but In the present invention, the plating species are not limited to Zn-11%Al-3%Mg-0.2%Si because the plating and chemical conversion treatment film disappears and scale is present. In the following examples, in addition to the above zinc alloy plating, a galvanized steel strip having a pure zinc plating layer with an adhesion amount of 140 g/m ² per side is also used for verification.

The plated welded steel section was cut at the center of the web to form a T-shaped test piece. A rust preventive film (resin layer and organic coating layer) was formed on the weld bead portion and the end portion of this test piece.

When forming the resin layer, an epoxy resin paint (trade name: Esba (registered trademark) 99 Silver) manufactured by Shinto Paint Co., Ltd. containing about 3% by mass of scaly aluminum pieces was used as a bright pigment. .. The resin was applied by spraying so that the resin film thickness would be the value and position shown in Table 1, and then dried to form a resin layer.

After forming the above-mentioned resin layer, about Examples 1-15 and 17, 18, after hardening for 18 hours at room temperature, the organic type coating layer was formed. An organic zinc rich primer (trade name: Zinc Primer R) manufactured by Shinto Paint Co., Ltd., which is an organic zinc rich paint, was used for forming the organic coating film layer. These coating materials are applied by spraying so that the film thickness of the organic coating layer becomes the value and position shown in Table 1, and then dried to form an organic coating layer (coating layer). did. On the other hand, in Example 16, after the resin layer was formed, curing was performed at room temperature for 1 hour, and then an organic coating layer was formed in the same manner.

Note that test pieces were prepared by changing the coating ranges of the resin layer and the organic coating layer. The pattern of this coating range is described in the coating layer pattern in Table 1. The application range will be described with reference to FIGS. 5A to 5H. 5A to 5H are cross-sectional views in the width direction that schematically show the laminated pattern of the test piece of the plated welded H-section steel. In FIGS. 5A to 5H, the end of the chemical conversion treatment film 101 on the flange closer to the weld bead is a, the end of the resin layers 103a to 103h on the flange farther from the weld bead is b, and the organic material on the flange is The end of the coating layers 105a to 105h on the side far from the weld bead is represented by c.

In FIG. 5A, an application range in which the end b of the resin layer 103a, the end c of the organic coating layer 105a, and the end a of the chemical conversion treatment film 101 are arranged in this order from the left side far from the bead 15 is shown. (Pattern A). In this case, more specifically, a resin layer 103a is formed on the chemical conversion treatment film 101 of the zinc-based plated steel strip constituting the flange material so as to cover a part of the film and the bead 15, and one of the resin layers 103a is formed. The organic coating layer 105 a was coated on the resin layer 103 so as to cover the portion and all the welding beads 15.

In FIG. 5B, the organic coating layer is omitted, and an application range in which the end b of the resin layer 103b and the end a of the chemical conversion coating 101 are arranged in this order from the left side far from the bead 15 is shown. (Pattern B). In this case, more specifically, the resin layer 103b was formed on the chemical conversion treatment film 101 of the zinc-based plated steel strip constituting the flange material so as to cover a part thereof and the bead 15.

In FIG. 5C, the resin layer is omitted, and an application range in which the end c of the organic coating layer 105c and then the end a of the chemical conversion coating 101 are arranged in this order from the left side far from the bead 15 is shown. (Pattern C). In this case, more specifically, the organic coating layer 105c was applied on the chemical conversion treatment film 101 of the zinc-based plated steel strip forming the flange material so as to cover a part of the conversion coating 101 and the bead 15.

In FIG. 5D, the coating range in which the end c of the organic coating layer 105d, the end b of the resin layer 103d, and the end a of the chemical conversion treatment film 101 are arranged in this order from the left side far from the bead 15 is shown. (Pattern D). In this case, more specifically, a resin layer 103d is formed on the chemical conversion treatment film 101 of the zinc-based plated steel strip constituting the flange material so as to cover a part thereof and the bead 15, and the entire resin layer 103d is formed. The organic coating layer 105d was applied so as to cover and directly cover the chemical conversion coating 101 near the end b of the resin layer 103d.

In FIG. 5E, an application range in which the end c of the organic coating layer 105e, the end a of the chemical conversion coating 101, and the end b of the resin layer 103e are arranged in this order from the left side far from the bead 15 is shown. (Pattern E). In this case, more specifically, the resin layer 103e is formed so as to cover only a part of the bead 15 of the zinc-based plated steel strip constituting the flange material, and the resin layer 103d and the bead 15 are covered to form the bead 15 An organic coating layer 105e was applied so as to directly cover a part of the chemical conversion treatment film 101 adjacent to.

In FIG. 5F, the coating range in which the end b of the resin layer 103f, the end a of the chemical conversion treatment film 101, and the end c of the organic coating layer 105f are arranged in this order from the left side far from the bead 15 is shown. (Pattern F). In this case, more specifically, a resin layer 103f is formed so as to cover a part of the zinc-based plated steel strip constituting the flange material and the bead 15, and one of the resin layers 103f is formed. The organic coating layer 105f was coated on the resin layer 103f so as to cover only a part and a part of the bead 15.

In FIG. 5G, the coating range is shown in which the end b of the resin layer 103g and the end c of the organic coating layer 105g are arranged from the end c of the bead 15 toward the inside of the bead 15. (Pattern G). In this case, more specifically, the resin layer 103g is formed so as to cover only a part of the bead 15 of the zinc-based plated steel strip constituting the flange material, and so as to cover only a part of the resin layer 103g, An organic coating layer 105g was applied on the resin layer 103g.

FIG. 5H shows an application range in which the end c of the organic coating layer 105h and the end b of the resin layer 103h are arranged from the end c of the bead 15 toward the inside of the bead 15. (Pattern H). In this case, more specifically, the resin layer 103h is formed so as to cover only a part of the bead 15 of the zinc-based plated steel strip that constitutes the flange material, and all of the resin layer 103g and part of the bead 15 are formed. An organic coating layer 105h was applied so as to cover the.

Further, in Example 17, after coating the above organic coating layer, curing was carried out at room temperature for 18 hours, and then, as a color matching coating, a coating layer containing a bright pigment was overcoated. The top coat film layer is formed by spray-coating an epoxy resin paint (trade name: Esba (registered trademark) 99 Silver) manufactured by Shinto Paint Co., Ltd. so as to have a film thickness of 15 μm, and then drying the top coat film layer. Formed. The top coating film layer was applied so as to cover the entire organic coating film layer 105.

Each of the samples obtained as described above was evaluated from three viewpoints of coating layer adhesion, corrosion resistance, and appearance after coating. The evaluation method is as follows.

The adhesion of the coating film layer was measured by using a commercially available cellophane tape (trade name: cellophane tape) after the test piece exposed to a humid environment at a temperature of 50° C. and a humidity of 98 RH or more for 120 hours was cut with a cutter knife to make a 2 mm cross-cut. (Registered trademark)) was used. The number density of the squares in which the coating layer remained at ½ square or more was evaluated, and 80/100 or more was evaluated as passing, and “◯” is shown in Table 1. Those having a number density of 90/100 or more in which the coating layer remained in the coating layer of ½ or more were particularly excellent in coating layer adhesion, and therefore “A” is shown in Table 1. In addition, those in which the number density was 79/100 or less were rejected, and "X" is shown in Table 1.

The corrosion resistance was evaluated by subjecting it to a corrosion test described in JIS H8502 without imparting scratches to the coating film layer, and those in which the red rust occurrence time was 75 cycles or more were accepted, and Table 1 shows "○". Is described. Since those having a red rust generation time of 90 cycles or more are particularly excellent in corrosion resistance, "1" is shown in Table 1. In addition, those in which the red rust generation time was less than 75 cycles were rejected, and "X" is shown in Table 1.

As for the appearance after coating, the appearance of the formed coating layer is visually evaluated, and a good one is described as "◎", and a color unevenness and sagging of the coating layer are indicated as "○". Is described.

As is clear from Table 1 above, it is clear that the samples corresponding to the examples of the present invention exhibit excellent coating layer adhesion, corrosion resistance, and appearance after coating, even without performing the blast treatment that is the base conditioning treatment. It was In addition, sample No. which was cured for a sufficient time. Nos. 3 to 7, 12, 13, 15, 17 to 18 are sample Nos. that were cured for a relatively short time. It showed a better appearance as compared with 16. On the other hand, the sample corresponding to the comparative example could not realize excellent coating layer adhesion and corrosion resistance. In addition, the sample No. Regarding 3 to 7 and 12 to 18, the resin layer was formed by applying quick epoprimer II manufactured by Shinto Paint Co., Ltd., which is a one-pack type modified epoxy resin paint, by spraying and then drying, It was confirmed that the same effect can be obtained when a coating material other than the resin coating material (trade name: Esba (registered trademark) 99 Silver) is used as the material of the resin layer.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

1 Plating welded H-section steel (plating welded lightweight H-section steel)
3 Flange 5 Web 7 Welded part 9 End face 11 Base material steel plate 13 Zinc system plating layer 15 Bead 101 Chemical conversion treatment film 103 Resin layer 105 Organic coating layer (organic zinc rich coating layer)

Claims (10)

A web made of a zinc-based plated steel sheet which is a plated steel sheet having a pure zinc plated layer or a zinc alloy plated layer ,
A zinc-based plated steel sheet which is a plated steel sheet having a pure zinc plated layer or a zinc alloy plated layer, and a flange welded to the web,
A weld bead located at the weld between the web and the flange,
A first coating located on the web and the flange, the first coating including zirconium and an organic acid;
A second coating that is positioned to cover at least a portion of the weld bead and at least a portion of the first coating, and that includes a resin material;
An organic third coating which is a coating containing an organic resin which is a binder component and zinc particles, and which is positioned so as to cover the welding bead and at least a part of the second coating;
With galvanized welded steel. The plated welded structural steel according to claim 1, wherein the second coating has a thickness of 3 to 30 µm. The resin material is configured to include Epoxy resins, plated welding shaped steel according to claim 1 or 2. The first coating has a ratio of 10 to 45 parts by mass of vanadium, 5 to 100 parts by mass of phosphorus, 0.1 to 20 parts by mass of cobalt, and 10 to 90 parts by mass of organic acid with respect to 100 parts by mass of zirconium. 4. The galvanized steel section according to claim 1, wherein The plating welding according to any one of claims 1 to 4, wherein the third coating film is an organic coating film layer containing 60% by mass or more of zinc particles with respect to the total mass of the third coating film. Shaped steel. The thickness of the said 3rd coating film is 5-200 micrometers, The plating welded steel shape as described in any one of Claims 1-5. At least a part of the end surface of the flange and at least a part of the first coating adjacent to the end surface, the second coating is located,
The galvanized steel section according to any one of claims 1 to 6, wherein the third coating is positioned on the second coating so as to cover the end surface of the flange. The galvannealed steel section according to any one of claims 1 to 7, further comprising a coating film containing a bright pigment, the coating film being located so as to cover at least a part of the third coating film. The galvanized steel section according to any one of claims 1 to 8, wherein a pair of flanges including the flange are galvanically welded H-section steels arranged to face each other via the web. A web made of a zinc-based plated steel sheet that is a plated steel sheet having a pure zinc-plated layer or a zinc alloy plated layer, and a zinc-based plated steel sheet that is a plated steel sheet having a pure zinc-plated layer or a zinc alloy plated layer, and welded to the web. Welded section steel, which comprises a formed flange, a weld bead located at a welding site between the web and the flange, and a first coating formed on the web and the flange and containing zirconium and an organic acid. On the other hand, forming a second coating including a resin material, which covers at least a portion of the welding bead and at least a portion of the first coating,
An organic resin as a binder component, which cures the plated welded steel having the second coating film formed thereon for at least 4 hours or more, and covers the welding beads and also covers at least a part of the second coating film. A method for producing a plated welded steel shape, which comprises forming an organic third film which is a film containing zinc particles.