JP6800603B2 - Manufacturing method of plated welded shaped steel and plated welded shaped steel - Google Patents

Description

The present invention relates to a plated welded section steel and a method for manufacturing a plated welded section steel.

Various lightweight shaped steels such as welded lightweight H-shaped steels are known. Of these, the welded lightweight H-shaped steel is an H-shaped steel formed by using hot-rolled steel strips, cold-rolled steel strips, or plated steel strips in combination with 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 for prefabricated houses, columns and beams of structures. In recent years, welded lightweight H-section steel has been used not only as a material for steel structures but also as a material for columns and beams in conventional wooden houses, and its demand is expanding.

In recent years, welded lightweight H-section steels have been studied for use in severe outdoor corrosion environments, as represented by gantry parts for photovoltaic power generation. When using a 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 are problems of shape change due to heat during plating and outsourced processing cost, and it is expected that a plated welded lightweight H-shaped steel obtained by forming a plated steel strip, for example, as disclosed in Patent Document 1 below, will be utilized.

Japanese Unexamined Patent Publication No. 2003-275814

The plated lightweight H-shaped steel as disclosed in Patent Document 1 is formed by using a plated steel strip that has been pre-plated and is continuously welded together, but the steel strip corresponding to the flange. When welding the steel strip corresponding to the web, the plating layer of the weld 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 face of the flange.

Welded parts and end faces that do not have a plating layer may be damaged by corrosion, so it is important to apply anticorrosion treatment suitable for the application environment, and a technology that can appropriately repair these parts where the plating layer is missing. Is sought after.

It is generally considered that the service life is proportional to the amount of plating adhesion, and in order to secure the same corrosion resistance as the plating on the flat surface, the same plating metal component as the plating on the flat surface should be secured with the same amount of adhesion. Is considered to be important. From this point of view, zinc-based thermal spraying and zinc powder-containing coating (hereinafter, also referred to as “zinc rich coating”) can be considered as repair technology candidates for ensuring sufficient corrosion resistance. However, thermal spraying, which is a dry process, cannot be easily processed because a dust countermeasure facility is required. Therefore, also in Patent Document 1, it is described that zinc spray coating is performed on the welded portion.

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

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

When blasting is performed to adjust the base material of the welded portion and end face of plated welded lightweight H-section steel in order to form a zinc rich coating film, the plated surface located near the welded portion and end face is also blasted. Will be done. In particular, when the end face is blasted, at least one of the front and back plated surfaces is greatly affected by the blasting. Therefore, in order to apply a zinc rich coating film for enhancing the corrosion resistance of the welded portion and the end face, the corrosion resistance of the plated surface located near the welded portion and the end face is affected, and the base material prior to the formation of the zinc rich coating film. It is considered unfavorable to adopt blasting as an adjustment. Under such circumstances, there is a demand for a substrate adjustment technique instead of blasting, particularly for welded portions of plated welded lightweight H-section steel.

On the other hand, when forming a rust preventive film such as a zinc rich coating film, the rust preventive film paint should contain a large amount of binder such as a resin material for the purpose of improving the adhesion of the rust preventive film to the substrate. Can be considered. However, plated-welded lightweight shaped steels such as plated-welded lightweight H-shaped steels may be used for welding with other members when used as building structural materials and the like. In such a case, the binder may ignite during welding and the vicinity of the surface of the plated welded lightweight shaped steel may deteriorate, or the conductivity may decrease due to a large amount of binder, and the welding stability may decrease. .. Therefore, it is required to maintain the weldability of the plated welded lightweight shaped steel even when the rust preventive film is formed.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to improve the corrosion resistance of the portion where the plating layer is missing, and at the same time, to have excellent weldability. It is an object of the present invention to provide a plated welded section steel and a method for manufacturing a plated welded section steel.

As a result of diligent studies by the present inventor in order to solve the above problems, a rust preventive film is placed in a portion where the plating layer is missing, and the rust preventive film contains other components of a metal component. It has been found that the above-mentioned problems can be solved by satisfying a predetermined index indicating the content of the above-mentioned material, and the method for producing the plated welded shaped steel and the plated welded shaped steel according to the present invention as described in detail below has been completed. ..
The gist of the present invention completed based on such findings is as follows.

[1] A web made of galvanized steel sheet and
A flange made of galvanized steel sheet and welded to the web,
A weld bead located at a welded portion between the web and the flange,
A rust preventive film that covers at least a part of the weld bead and contains a metal component is provided.
The metal component contains particles having a sacrificial anticorrosive effect on iron.
The content M of the metal component in the rust preventive film is 50 to 98% by mass with respect to the total mass of the rust preventive film.
I _w represented by the following formula (1) is 19.3 to 30 μm.
The thickness of the rust preventive film is 70 to 130 μm, plated welded shaped steel,
I _w (μm) = T (μm) × (100-M (mass%)) / 100 ... (1)
However, in the formula (1), T is the thickness (μm) of the rust preventive film, and M is the content (mass%) of the metal component in the rust preventive film.
[ 2 ] The plated welded shaped steel according to [1 ], wherein the particles having a sacrificial anticorrosion effect are composed of one or both of aluminum and zinc.
[ 3 ] The plated welded shaped steel according to [1] or [2] , wherein the rust preventive film is composed of a zinc rich coating film.
[ 4 ] At least a part of the rust preventive film is
Cover the web with a width of 2 to 25 mm from the boundary between the weld bead and the web along the surface of the web, and from the boundary between the weld bead and the flange toward the widthwise end face of the flange. To cover the flange with a width of 2 to 25 mm.
The plated welded shaped steel according to any one of [1] to [ 3 ], which is arranged along the weld bead.
[ 5 ] At least a part of the rust preventive film is
From the boundary between the weld bead and the web along the surface of the web, cover with a width of 2 to 45% of the width of the web, and from the boundary between the weld bead and the flange to the flange. Toward the widthwise end face, cover the flange with a width of 3 to 65% of the distance between the boundary and the widthwise end face of the flange.
The plated welded shaped steel according to any one of [1] to [ 3 ], which is arranged along the weld bead.
[ 6 ] The plated welded shaped steel according to any one of [1] to [ 5 ], wherein the rust preventive film is located so as to cover at least a part of the end face of the flange.
[ 7 ] The rust preventive film is a laminated body containing a plurality of layers, and is a laminate.
The plated welded shaped steel according to any one of [1] to [ 6 ], wherein at least one of the plurality of layers contains the metal component.
[ 8 ] The plated welded shaped steel according to [ 7 ], wherein at least a part of the outermost layer of the plurality of layers of the rust preventive film is a coating film containing a bright pigment.
[ 9 ] Further, a zirconium-containing film located on the web and / or the flange and composed of a zirconium element and an organic acid is provided.
The plated welded shaped steel according to any one of [1] to [ 8 ], wherein at least a part of the rust preventive film is located on the zirconium-containing film.
[ 10 ] The plating weld according to any one of [1] to [ 9 ], which is a plated welded H-section steel in which a pair of flanges including the flange are arranged so as to face each other via the web. Shaped steel.
[ 11 ] It is used for welding with further members.
The plated welded section according to any one of [1] to [ 10 ], wherein the rust preventive film is not arranged at a portion to be welded to the flange and / or the member of the web.
[ 12 ] Plating welding including a web made of a zinc-based plated steel plate, a flange made of a zinc-based plated steel plate welded to the web, and a weld bead formed at a welded portion between the web and the flange. It has a step of coating at least a part of the weld bead of the shaped steel with a rust preventive film.
The rust preventive film contains a metal component containing particles having a sacrificial anticorrosive effect on iron.
The content M of the metal component in the rust preventive film is 50 to 98% by mass with respect to the total mass of the rust preventive film.
I _w represented by the following equation (1) is 19.3 μm to 30 μm.
A method for producing a plated welded section steel, wherein the thickness of the rust preventive film is 70 to 130 μm.
I _w (μm) = T (μm) × (100-M (mass%)) / 100 ... (1)
However, in the formula (1), T is the thickness (μm) of the rust preventive film, and M is the content (mass%) of the metal component in the rust preventive film.

As described above, according to the present invention, there is provided a method for producing a plated welded section steel and a plated welded section steel, which have excellent corrosion resistance at a portion where the plating layer is missing and at the same time have excellent weldability. It is possible.

It is a cross-sectional view in the width direction which schematically shows the structure of the plated welded section steel which concerns on embodiment of this invention. It is a cross-sectional view in the width direction which expanded and showed the structure near the flange of the plated welded section steel in the same embodiment. It is an electron micrograph of a plated welded H-beam showing a layer structure of a plated welded H-beam. It is a perspective view of the sample piece used for the weldability evaluation of a plated welded section steel. It is a perspective view of the sample piece used for the weldability evaluation of a plated welded section steel. It is a perspective view of the sample piece used for the weldability evaluation of a plated welded section steel.

Preferred embodiments of the present invention will be described in detail below 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, so that duplicate description will be omitted.

(About plated welded shaped steel)
Hereinafter, the plated welded lightweight shaped steel (hereinafter, also simply referred to as “plated welded shaped steel”) according to the embodiment of the present invention will be described in detail with reference to FIGS. 1 to 2.
FIG. 1 is a cross-sectional view in the width direction schematically showing the structure of the plated welded section steel according to the present embodiment. FIG. 2 is a cross-sectional view in the width direction showing an enlarged structure of the plated welded section near the flange in the present embodiment.

<About the overall structure of plated welded shaped steel>
First, the overall structure of the plated welded section steel 1 according to the present embodiment will be described in detail with reference to FIG.
The plated welded lightweight shaped steel 1 according to the present embodiment is a plated welded H-shaped steel. In the plated welded lightweight shaped steel 1, for example, a coil obtained by winding a zinc-based plated steel strip is rewound and slit to a predetermined width to form a flange steel strip, and a coil wound by a zinc-based plated steel strip is wound. It is manufactured by continuous welding by high-frequency resistance welding, high-frequency induction welding, etc., with the steel strip for the web being returned and in contact with it.

As shown schematically in FIG. 1, the plated welded shaped steel 1 produced in this manner includes a pair of flanges 3 provided so as to face each other, a web 5 connecting the two flanges 3, and a web 5. It is composed of.

In the plated welded structural steel 1 according to the present embodiment, the width and thickness of the flange 3 or the web 5 are not particularly limited. For example, the plated welded shaped steel 1 is a typical plated welded H-shaped 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 plated welded structural steel 1 according to the present embodiment, as described above, the zinc-based plated steel strip serving as the flange 3 and the zinc-based plated steel strip serving as 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 plated welded section steel 1 according to the present embodiment, since a zinc-based plated steel strip is used as a raw material, zinc is used on the surface layer of the steel plate as the base material (hereinafter, also simply referred to as “base steel plate”) 11. The system plating layer 13 is formed. However, due to the heat generated by the above welding process, the zinc-based plating layer 13 does not exist in the welded portion 7. Further, the zinc-based plating layer 13 is often not present even on the end surface 9 of the flange 3.

Therefore, in the plated welded structural steel 1 according to the present embodiment, the welded portion (welded) is the portion that is the region near the connecting portion between the flange 3 and the web 5 and in which the zinc-based plated layer 13 does not exist. Part) 7 can be considered. Further, since the zinc-based plated steel strip serving as the flange 3 and the zinc-based plated steel strip serving as the web 5 are welded while being pressure-welded, a bead (welding bead) 15 is generated immediately after welding. .. In the plated welded structural steel 1 according to the present embodiment, the bead 15 is formed by crushing the bead 15 with a roller or the like after welding, and the bead 15 is viewed from the side surface as schematically shown in FIG. The shape is approximately triangular. Therefore, in the plated welded shaped steel 1 according to the present embodiment, the portion where the beads 15 exist 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 steel sheet 11 is not particularly limited, and a steel sheet usually used as a base plate for a zinc-based plated steel sheet can be appropriately used. The manufacturing method, material, etc. of this original plate are not particularly limited, and those manufactured through processes such as hot rolling, pickling, cold rolling, annealing, and temper rolling from a normal steel piece manufacturing process are not particularly limited. You can use it. Further, the original plate may be formed with a chemical conversion treatment coating as described later.

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

In the plated welded shaped steel 1 according to the present embodiment, by using the zinc-based plated steel sheet on which the zinc-based plated layer 13 is formed as a raw material, the corrosion resistance of the shaped steel as a whole is improved by the sacrificial anticorrosion ability of zinc. It becomes possible to secure.

The thickness and the amount of adhesion of the zinc-based plated layer 13 are not particularly limited, and may be appropriately set according to the required performance, cost, and the like of the plated welded shaped 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 surface, more preferably about 20 μm per side surface. When the thickness of the zinc-based plating layer 13 is less than 1 μm, it becomes difficult to realize the sacrificial anticorrosion ability of zinc, which is not preferable. Further, when the thickness of the zinc-based plating layer 13 exceeds 80 μm, the economical cost increases, 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} .

<About the structure of the weld>
Subsequently, the structure of the welded portion 7 of the plated welded structural steel 1 according to the present embodiment will be specifically described with reference to FIG.

As described above, in the plated welded shaped steel 1 according to the present embodiment, when the flange 3 and the web 5 are connected by welding, the zinc-based plated layer 13 formed on the surface of the base steel plate 11 is formed. It will be removed. Therefore, the corrosion resistance of the welded portion 7 is lower than that of the portion where the zinc-based plating layer 13 is formed.

Therefore, the present inventors have proposed to form a rust preventive film 101 on the welded portion 7. In addition, when the rust preventive film 101 is formed, the present inventors of the plated welded shaped steel 1 when the rust preventive film 101 satisfies a predetermined relationship between the metal component and the other components. It was found that the weldability is excellent. The rust preventive film 101 will be described later.

Therefore, in the welded portion 7 of the plated welded H-shaped steel 1 according to the present embodiment, as shown in FIG. 2, the base steel plate 11 as a base is present in the cross-sectional structure thereof, and Fe is provided on the base steel plate 11. There is a bead 15 containing the above as a main component. Then, the rust preventive film 101 is formed so as to cover the bead 15. With the layer structure as described above, the corrosion resistance of the bead 15 is ensured by the rust preventive film 101 even in the welded portion 7 in which the zinc-based plating layer 13 does not exist.

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

Therefore, as shown in FIG. 2, the rust preventive film 101 is also formed on the end face 9 so as to cover the end face 9 of the base steel plate 11.

With the layer structure as described above, even when the zinc-based plating layer 13 does not exist on the end face 9, the rust preventive film 101 ensures the corrosion resistance of the base steel sheet 11 on the end face 9. It becomes.

The overall configuration of the plated welded section 1 according to the present embodiment has been described above. Next, the rust preventive film 101 arranged on the above-mentioned plated welded shaped steel 1 will be described in detail.

<About rust preventive film 101>
Subsequently, the rust preventive film 101 formed on the welded portion 7 and the end face 9 of the plated welded shaped steel 1 according to the present embodiment will be described in detail.

The rust preventive film 101 prevents corrosion of the bead 15 of the welded portion 7 and the base steel plate 11 of the end face 9 by covering them.
Further, the rust preventive film 101 contains a metal component. In the present embodiment, such a metal component contains particles having a sacrificial anticorrosion ability against iron (hereinafter, also referred to as “sacrificial anticorrosion particles”). When the plated welded section 1 is under oxidizing conditions, the consumption of such sacrificial anticorrosion particles prevents oxidation of the base steel sheet 11 and prevents the occurrence of rust.

On the other hand, in order to ensure that the rust preventive film 101 has the above-mentioned corrosion prevention ability, the rust preventive film 101 exists in close contact with the base steel plate 11 of the bead 15 and the end face 9, and these are present. It is necessary to cover it. Therefore, the rust preventive film 101 contains an organic or inorganic binder for bringing the bead 15 into close contact with the base steel plate 11 of the end face 9. However, components other than such metal components may ignite during welding and deteriorate peripheral parts such as the zinc-based plating layer 13, affect conductivity, and reduce welding stability, or in some cases. May give off an odor due to combustion.

Therefore, in the present embodiment, the rust preventive film 101 is configured such that I _w represented by the following formula (1) is 0.5 to 30 μm.
I _w (μm) = T (μm) × (100-M (mass%)) / 100 ... (1)
However, in the formula (1), T is the thickness (μm) of the rust preventive film 101, and M is the content (mass%) of the metal component in the rust preventive film 101.

When I _w satisfies the above range, the corrosion resistance and weldability of the plated welded section steel 1 can be made excellent at the same time. Therefore, it is possible to prevent components other than the metal component of the rust preventive film 101 from catching fire or lowering the stability of welding during welding. On the other hand, if I _w is smaller than the above lower limit value, the rust preventive film 101 cannot be sufficiently brought into close contact with the base steel plate 11 of the bead 15 and the end face 9, so that the corrosion resistance of the plated welded section steel 1 is particularly high. The corrosion resistance of the base steel plate 11 of the bead 15 and the end face 9 is not sufficient. Further, when I _w is larger than the above upper limit value, a large amount of components other than the metal component are contained in the rust preventive film 101, and the weldability of the plated welded section steel 1 cannot be improved.

I _w may be within the above range, but is preferably 1.0 to 27 μm, and more preferably 1.5 to 25 μm. Thereby, the above-mentioned effect can be obtained more remarkably.

The content M (mass%) of the metal component is not particularly limited, but can be, for example, 50 to 98% by mass, preferably 55 to 96% by mass, based on the total mass of the rust preventive film. It is preferably 58 to 95% by mass. As a result, sufficient sacrificial anticorrosion works and corrosion resistance is ensured.

Further, in the present embodiment, the thickness of the rust preventive film 101 is 30 to 130 μm. When the thickness of the rust preventive film 101 is within the above range, the corrosion resistance and weldability of the plated welded section steel 1 can be made sufficiently excellent. On the other hand, if the thickness of the rust preventive film 101 is smaller than the above lower limit value, the effect of improving the corrosion resistance of the rust preventive film 101 cannot be sufficiently obtained. Further, if the thickness of the rust preventive film 101 is larger than the above upper limit value, there is a problem that, for example, sufficient conductivity cannot be obtained and welding becomes difficult.

The thickness of the rust preventive film 101 may be within the above range, but is preferably 40 to 120 μm, and more preferably 50 to 90 μm. Thereby, the above-mentioned effect can be obtained more remarkably.

In the present embodiment, the rust preventive film 101 is not particularly limited as long as it is as described above, but the rust preventive film 101 will be described more specifically below.

As described above, the rust preventive film 101 contains sacrificial anticorrosive particles as a metal component. The sacrificial anticorrosion particles are not particularly limited as long as they exert a sacrificial anticorrosion effect on iron as described above. For example, nickel, nickel alloy, brass, aluminum, magnesium, zinc, zinc-aluminum alloy, aluminum-iron. Examples thereof include alloys and fine particles such as Al ₂ Mg ₃ Zn ₃ , Mg Zn, and Mg Zn ₂ .

Among the above, the sacrificial anticorrosion particles are preferably composed of a metal that is more base than iron. Further, the sacrificial anticorrosion particles are preferably composed of one or both of aluminum and zinc, and more preferably composed of zinc. As a result, the sacrificial anticorrosion effect of the sacrificial anticorrosion particles can be made sufficiently high, and the corrosion resistance of the plated welded shaped steel 1 can be made sufficiently high.

Among them, a coating film containing a large amount of zinc is known as a zinc rich coating film. The rust preventive film 101 can be configured to include such a zinc rich coating film. Zinc-rich paints for forming zinc-rich coatings are roughly classified into water-based zinc-rich paints and solvent-based zinc-rich paints according to the solvent used, and organic zinc-based paints are classified according to the type of binder component used. It is roughly divided into rich paint and inorganic zinc rich paint.

The zinc rich paint used for forming the rust preventive film 101 preferably contains 50% by mass or more of zinc powder as a main component with respect to the entire non-volatile component (solid content). Here, the content of the zinc powder contained in the zinc rich paint is the content of the zinc powder contained in the rust preventive film 101. By containing the zinc powder having the above-mentioned content, the rust preventive film 101 can realize excellent sacrificial anticorrosive ability. The content of the zinc powder contained in the zinc rich paint is more preferably 80% by mass to 98% by mass.

Further, the zinc rich paint may further contain elements such as aluminum, magnesium, silicon, iron and nickel as long as the zinc powder is contained in an amount of 50% by mass or more. The content of these elements is not particularly limited, but is preferably, for example, 5% by mass to 40% by mass, preferably 6 to 20% by mass.

The shape of the zinc powder contained in the rust preventive film 101 is not particularly limited, and may be any shape such as spherical, rod-shaped, lump-shaped, needle-shaped, or may be blended. The average particle size of the zinc powder contained in the rust preventive film 101 is preferably 0.1 μm to 100 μm, and more preferably 0.1 μm to 50 μm. The average particle size of the zinc powder can be measured by using a known method such as a dynamic light scattering method, an induction diffraction grating method, or a laser diffraction / scattering method. The same applies to sacrificial anticorrosion particles other than zinc powder.

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

Such an organic binder component is not particularly limited, and may be, for example, a resin containing an epoxy resin, an acrylic resin, a urethane resin and / or a polyester resin as described above.

Specific examples of the epoxy resin include EPICLON (registered trademark) 840 and 850 series manufactured by DIC, which are bisphenol A type epoxy resins. It is advantageous to have a low viscosity 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 Acrydic (registered trademark) A-1371 and A-1381 series, which are acrylic resins for forced drying at room temperature.

Specific examples of the urethane-based resin include moisture-curable, lacquer-type, and oil-modified urethane resins. As such a urethane-based resin, for example, the urethane resin BURNOCK (registered trademark) series manufactured by DIC can be exemplified.

Specific examples of the polyester resin include a blocked isocyanate curable polyester resin and a saturated polyester resin. Examples of such polyester-based resins include Finedick (registered trademark) M8020 series manufactured by DIC and Yupica Coat GV110 series manufactured by Japan U-Pica.

Examples of the inorganic binder include traalkoxysilicates, alkyltrialkoxysilicates, dialkyldialkoxysilicates, etc., and hydrolysis of partial condensates of these silicates and / or condensation reactions of these silicates in the presence of water and an acid catalyst. An inorganic binder resin containing silicon, such as a condensate, can be used.

Here, examples of the tetraalkoxysilicate include tetramethoxysilicate, tetraethoxysilicate, tetrapropoxysilicate, tetraisopropoxysilicate, tetrabutoxysilicate, tetraisobutoxysilicate and the like. Examples of the alkyl trialkoxy silicate include methyl trimethoxy silicate, methyl triethoxy silicate, methyl tripropoxy silicate, ethyl trimethoxy silicate, and ethyl triethoxy silicate. In addition, examples of the dialkyldialkoxysilicate include dimethyldimethoxysilicate, dimethyldiethoxysilicate, diethyldimethoxysilicate, diethyldiethoxysilicate and the like. These silicate compounds may be used alone or in combination of two or more. Further, colloidal silica such as water-dispersed colloidal silica and solvent-dispersed colloidal silica may be used in combination with the silicate compound.

Further, as an inorganic binder component, a component other than silicon, such as a metal alkoxide, a metal colloid, or a polyvinyl alcohol resin, may be added, if necessary.

If necessary, ordinary extender pigments, rust preventive pigments, coloring pigments and the like may be added to the zinc rich paint used for forming the rust preventive film 101 to the extent that the fineness of the coating film is not impaired. .. Examples of extender pigments include silica powder, barium sulfate, calcium carbonate, talc, kaolin, clay, and silica balloons. Examples of rust preventive pigments and coloring pigments include titanium oxide, iron phosphate, and mica. Examples thereof include iron oxide, lead cyanamide, zinc chromate, zinc phosphate, calcium phosphate, barium metaborate, zinc molybdenate, aluminum molybdenate, red iron oxide, cyanine-based coloring pigment, carbon black, rutile powder, and zircon powder.

Further, in the zinc rich paint used for forming the rust preventive film 101, if necessary, usual paint additives such as a settling inhibitor, a sagging preventive agent, a wetting agent, a reaction accelerator, and an adhesion imparting agent are added. May be added as appropriate.

The thickness of the zinc-rich coating film formed by using the zinc-rich coating material as described above is preferably about twice the thickness of the zinc-based plating layer 13 formed on the base steel plate 11. By making the thickness of the zinc-rich coating film about twice the thickness of the zinc-based plating layer 13, the rust-preventive film 101 can realize almost the same corrosion resistance as the zinc-based plating layer 13. ..

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

As a specific example of the rust preventive film 101 containing sacrificial anticorrosive particles, a zinc rich coating film when zinc powder is used has been described above. Here, in the case of sacrificial anticorrosion particles other than zinc, it can be configured in the same manner as the zinc rich coating film as described above, and a coating material can be prepared in the same manner.

Further, the rust preventive film 101 may be composed of only the layer containing the sacrificial anticorrosive particles as described above, and can be formed by using one or both of the organic zinc rich paint and the inorganic zinc rich paint. .. In consideration of the adhesion of the rust preventive film 101, an organic zinc-rich coating film and an inorganic zinc-rich coating film are formed in this order on the bead 15 or the base steel plate 11 (zinc-based plating layer 13). May be good. Further, the rust preventive film 101 may be a multi-layered laminate composed of a layer containing sacrificial anticorrosive particles and another resin layer. Considering the adhesion, the rust preventive film 101 may be composed of, for example, a layer containing sacrificial anticorrosive particles and a resin layer arranged between the layer and the bead 15 or the base steel plate 11. it can. Such a resin layer can have high adhesion between the layer containing the sacrificial anticorrosion particles and the bead 15 or the base steel plate 11. Further, in consideration of corrosion resistance, for example, a resin layer may be provided on the upper layer of the layer containing the sacrificial anticorrosion particles. Such a resin layer can enhance the corrosion resistance of the layer containing the sacrificial anticorrosion particles of the base. That is, the resin layer arranged on the layer containing the sacrificial anticorrosion particles functions as a surface protective coating layer for protecting the base steel plate 11 and the layer containing the sacrificial anticorrosion particles.

As the resin material for forming the resin layer, the same resin as those listed in the above-mentioned organic binder can be used. The thickness of the resin layer is not particularly limited as long as the rust preventive film 101 can achieve the above-mentioned thickness, but is, for example, 3 to 30 μm, preferably 5 to 20 μm, and more preferably 7 to 15 μm. In the case of the above range, the adhesion between the steel component located in the lower layer and the upper layer and the corrosion resistance until the upper layer is formed can be sufficiently ensured. Further, when the thickness of the resin layer is within the above range, the time required for painting and drying can be relatively shortened, and the workability in forming the resin layer is improved.

As shown schematically in FIGS. 1 and 2, the rust preventive layer 101 according to the present embodiment is not only the base steel plate 11 on the bead 15 and the end face 9, but also the zinc-based plating layer 13 on the peripheral edge thereof. It is also placed above. As a result, the base steel plate 11 of the bead 15 and the end face 9 can be surely covered with the rust preventive film 101, and the corrosion resistance of the portion where the zinc-based plating layer 13 is missing can be made sufficiently high.

However, when it is known that the plated welded section steel 1 is used for welding with other members, the rust preventive film 101 is formed on the flange 3 and / or the web 5 at the planned welding site with other members. Is not arranged. As a result, the weldability of the plated welded section steel 1 at the planned welding portion can be made sufficiently high.

Further, in the rust preventive film 101 shown in FIG. 1, the widths that cover the web 5 from the boundary between the bead 15 and the web 5 toward the height along the surface of the web 5, such as W _c1 and W _c2, are preferable. Is 2 to 25 mm, more preferably 5 to 20 mm. Further, the widths W _c1 and W _c2 are preferably ₂ to 45%, more preferably ₂ to 45% of the distances W _w1 and W _w2 between the boundary portion between the bead 15 and the web 5 and the end face in the height direction of the web 5. Is 5 to 35%. As a result, in the web 5, it is possible to sufficiently secure a region having good weldability for welding other members.

Similarly, in the rust preventive film 101 shown in FIG. 2, the width that covers the flange 3 from the boundary between the bead 15 and the flange 3 toward the widthwise end face of the flange 3, for example, W _c3 is preferably 2 to 25 mm. More preferably, it is 5 to 20 mm. Further, the width W _c3 is preferably 3 to 65%, more preferably 5 to 50%, with _respect to the distance W _f between the boundary portion between the bead 15 and the flange 3 and the widthwise end surface of the flange 3. is there. As a result, in the flange 3, it is possible to sufficiently secure a region having good weldability for welding other members.

Further, the rust preventive film 101 formed on the base steel plate 11 of the end face 9 also covers the flange 3 from the end face 9 in the width direction of the flange 3. In this case, the width W _c4 that covers the flange 3 from the end surface 9 of the rust preventive film 101 in the width direction of the flange 3 is preferably 2 to 10 mm, more preferably 5 to 8 mm. Further, the width W _c4 is preferably 2 to 25%, more preferably 5 to 20, with _respect to the distance W _f between the boundary portion between the bead 15 and the flange 3 and the end face in the width direction of the flange 3. %. As a result, in the flange 3, it is possible to sufficiently secure a region having good weldability for welding other members.

The configuration of the plated welded structural steel 1 according to the present embodiment has been described above with reference to FIGS. 1 and 2.

A coating film containing a bright pigment can be arranged on at least a part of the outermost layer of the rust preventive film 101 of the plated welded shaped steel 1 (not shown). Normally, since the gloss of the zinc rich coating film is low, the repair-painted portion may be conspicuous depending on the application, and the designability may be impaired. However, by arranging the coating film containing the brilliant pigment on the outermost layer of the rust preventive film 101, it is possible to finish the appearance in a metallic tone similar to that of a sound portion in which the plating layer is not missing.

Such brilliant pigments are not particularly limited, and examples thereof include metal pieces such as aluminum, effect pigments such as glass flakes, silica flakes, and 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 film 105 can be made less noticeable.
Further, the coating film containing the above-mentioned bright pigment can be formed by, for example, applying a paint containing a resin material such as an epoxy resin by spraying or the like.

The coating film containing such a bright pigment can be formed not only on a part or all of the above-mentioned rust preventive film 101 but also on the entire surface of the plated welded shaped steel 1.

Further, a chemical conversion treatment film may be formed on the web 5 and the flange 3 of the plated welded section steel 1. Examples of such a chemical conversion-treated film include a zirconium-containing film composed of a zirconium (Zr) element and an organic acid. The chemical conversion coating is preferably composed of a vanadium (V) element, a phosphorus (P) element and a cobalt (Co) element in addition to the zirconium element and the organic acid as components.

The organic acid is not particularly limited, but for example, glycolic acid, malic acid, tartaric acid, oxalic acid, citric acid, ascorbic acid, lactic acid, dehydrobenzoic acid, dehydroascorbic acid, gallic acid, tannic acid, etc. Examples include phytic acid.

Such a chemical conversion-treated coating is a composite coating having a dense three-dimensional structure, excellent barrier properties, and improved corrosion resistance. In such a composite film, a dense three-dimensional network structure is formed mainly by Zr-O by coordinating 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 structures, and zinc and the like released by etching the plating surface are further incorporated. In the above-mentioned three-dimensional structure by Zr-O, some Zr may be replaced with other elements. Further, by etching the plating surface with an organic acid when forming the chemical conversion treatment film, the adhesion at the interface between the film and the plating surface is increased, and the corrosion resistance and the coating adhesion are improved.

The chemical conversion coating preferably contains 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 to 100 parts by mass 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 film may contain components other than those described above.

Such a chemical conversion coating can make the web 5 and the flange 3 sufficiently high in corrosion resistance. On the other hand, depending on the composition of the paint, it may be difficult for the paint to adhere to such a chemical conversion coating film, but the rust preventive film 101 of the present embodiment has an I _w as described above within a predetermined range. Therefore, it can be sufficiently adhered to the chemical conversion treatment film.

When the coating film containing the brilliant pigment as described above overlaps with the rust preventive film 101 described above, it is preferable that the laminated film in which all of these coating films are laminated is the rust preventive film described above. It is preferable to satisfy the thickness range of 101 and the range of I _w .

Further, although the plated welded shaped steel 1 according to the present embodiment has been described as being a plated welded H-shaped steel, the present invention is not limited thereto. For example, the plated welded section according to the present invention may be, for example, a welded T-shaped steel, a welded channel steel, a welded column, or a welded deformed steel.

<About the manufacturing method of plated welded shaped steel>
Next, a method for manufacturing a plated welded shaped steel will be described.
In the method for producing a plated welded section steel according to the present embodiment, a web 5 made of a zinc-based plated steel plate, a flange 3 made of a zinc-based plated steel plate and welded to the web 5, and welding of the web 5 and the flange 3 are performed. It has a step of coating at least a part of the bead 15 formed at the portion and the bead 15 of the plated welded shaped steel 1 provided with the rust preventive film 101.

First, as the plated welded steel 1 before coating the rust preventive film 101, for example, as described above, the coil wound with the zinc-based plated steel strip is rewound and slit to a predetermined width to form a flange steel strip. By continuously welding the product and the steel strip for the web by rewinding the coil wound from the zinc-based plated steel strip by high-frequency resistance welding, high-frequency induction welding, etc. in a state of being in contact with each other. , Manufactured.

Next, the rust preventive film 101 is formed on the bead 15 of the plated welded section 1 and the base steel plate 11 of the end face 9. The method for forming the rust preventive film 101 is not particularly limited, and a paint constituting the rust preventive film 101, for example, a zinc rich paint, is applied to the base steel plate 11 on the bead 15 and the end face 9 of the welded portion 7. It can be formed by spray painting. Further, the adhesion amount may be controlled by rolling or spraying gas so as to have a predetermined adhesion amount, or the zinc rich paint may be applied with a roll coater or the like. The rust preventive film 101 is formed by applying the zinc rich paint and then drying it. When forming a thick rust-preventive film 101, or when forming a rust-preventive film 101 composed of an organic zinc-rich coating film and an inorganic zinc-rich coating film, the application and drying of the zinc-rich paint are repeated as appropriate. You may.

When the rust preventive film 101 is a laminate of a resin layer and a layer containing sacrificial anticorrosive particles, the rust preventive film 101 can be formed by appropriately repeating application and drying of the paint as described above. is there.

Further, when manufacturing the plated welded structural steel 1, the index I _w is calculated in advance from the content of the metal component contained in the paint used for forming the rust preventive film and the desired thickness of the rust preventive film. It is preferable to appropriately select the paint to be used and adjust the thickness of the rust preventive film. When the rust preventive film is a laminated body of multiple layers, the content of metal components contained in the paint used (M ₁ , M ₂ , ... M _i ) and the thickness of each layer of the rust preventive film (T ₁ , T _2, because · · · _{T i)} and can be obtained an index _{I w} by the following equation (2).

_{I w (μm) = T 1} (μm) × (100-M 1 ( _{mass%)) / 100 + T 2} (μm) × (100-M 2 ( _{wt%)) / 100+ ··· + T} i (μm) × _{(100-M i} (mass%)) / 100 (2)
In the formula _{(2), T 1, T} 2, ··· T i is the thickness of each layer constituting the anti-corrosion film _{(μm), M 1, M} 2, ··· M i is , The content (mass%) of the metal component in each layer constituting the rust preventive film.

As described above, the plated welded shaped steel 1 according to the present embodiment is manufactured. In such a plated welded shaped steel 1, the corrosion resistance of the portion where the zinc-based plated layer 13 is missing, and by extension, the corrosion resistance of the entire plated welded shaped steel 1 is sufficiently high due to the rust preventive film 101. Further, since the rust preventive film 101 has a predetermined thickness and a value of I _w , the weldability is excellent despite the presence of the rust preventive film 101.

<Measurement method, etc.>
Subsequently, various measurement methods relating to the rust preventive film 101 on the welded portion 7 and the end face 9 of the plated welded shaped steel 1 according to the present embodiment will be briefly described.

The index I _w of the rust preventive film 101 can be calculated by measuring the thickness T (μm) of the rust preventive film 101 and the content M (mass%) of the metal component in the rust preventive film as follows. Even when the rust preventive film 101 is a laminated body of a plurality of layers, the total thickness T of the rust preventive film 101 and the content M of the metal component contained in the rust preventive film 101 may be measured.

The thickness T of the rust preventive film 101 is determined by, for example, masking a part of the flat plate test piece and then painting, and measuring the film thickness difference between the unpainted portion and the painted portion with, for example, an electromagnetic film thickness meter. Can be measured. Further, in a shape portion such as a weld bead, the film of the rust preventive film 101 is formed by observing the cross section of a sample cut out from the painted plated welded section steel using a scanning electron microscope (SEM). The thickness can be measured. The measurement can be performed in the same manner whether the rust preventive film 101 is a single layer or a laminated body having a plurality of layers.

On the other hand, the content M of the metal component of the rust preventive film 101 may be measured by cutting out a sample from the plated welded shaped steel on which the rust preventive film 101 is formed in a certain area and dissolving the coating component with a solvent, an acid or the like. For example, inductively coupled high frequency plasma emission spectroscopic analysis (ICP-AES) and inductively coupled high frequency plasma mass analysis (Inductively Coupled Plasma-MS) Mass-Mass Can be quantified using.

Further, the presence of the rust preventive film 101 formed on the welded portion 7 and the end face 9 of the plated welded shaped steel 1 according to the present embodiment is a cross section of a sample cut out from the manufactured plated welded shaped steel as described above. It can be confirmed by observing with SEM. In addition, by observing the cross section by SEM, it can also be confirmed that the blasting treatment is not performed as the base material adjustment for forming the rust preventive film 101. Further, by observing the cross section by SEM, it is possible to observe and measure the thickness and the existence range of the rust preventive film 101.

As a specific confirmation method, for example, the following method can be mentioned.
Here, as a more specific example, a film is applied to a welded portion of a plated welded H-beam made of a zinc-based plated steel strip and joined to a web and a flange, which is not blasted and has a scale. An organic zinc rich coating containing granular zinc powder was applied so as to have a thickness of about 70 μm.

This welded H-section steel was cut out including the weld bead portion. As an observation protective coating film for protecting the surface of the cut-out sample, the surface was protected with a quick-drying paint, and then embedded in an embedding resin. After solidification, the cross section was buffed. Then, C vapor deposition was performed to prevent charge-up. The results of SEM observation are shown in FIG. 3 below. The magnification of the SEM photograph of FIG. 3 is 20 times.

As is clear from FIG. 3, a scale corresponding to the bead of the welded H-shaped steel is observed in the upper layer of the steel, and a resin layer, a rust preventive film composed of a zinc rich coating film, and a protective coating for observation are further observed in the upper layer of the scale. The film was observed, and the film thickness of the rust preventive film could be evaluated. Furthermore, as a result of observing the scale, it was confirmed that the blast treatment was not performed.

Further, with respect to the end face 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 described above, and the cross section thereof is observed by SEM to determine the existence range and thickness of the rust preventive film. It becomes possible to measure.

As described above, various measurement methods relating to the rust preventive film 101 on the welded portion 7 and the end face 9 of the plated welded shaped steel 1 according to the present embodiment have been briefly described.

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

In the following, plated welded H-section steel and flat plate test pieces were manufactured, and their corrosion resistance and weldability were evaluated.

In the following, using a plated welded H-shaped steel manufactured using a general zinc-based plated steel strip, the following treatment is applied to the welded portion between the web and the flange of the plated welded H-shaped steel. Carried out. The component of the zinc alloy-based plating layer formed on the zinc-based plated steel strip used is Zn-11% Al-3% Mg-0.2% Si in mass%. The amount of adhesion of the zinc alloy-based plating layer of the zinc-based plated steel strip was 140 g / m ² per side. Further, it has been confirmed that the welded portion of the plated welded H-section steel used below has a bead composed of a component of the base steel sheet and a scale containing iron oxide as a main component. In some examples, those in which a chemical conversion coating film was formed on a zinc-based plated steel strip were used. The chemical conversion coating is formed by applying an aqueous solution containing a basic zirconium compound, vanadyl (VO ²⁺ ) -containing compound, phosphoric acid compound, cobalt compound and organic acid salt on both sides of a zinc-based plated steel strip by roll coating and drying. Formed by The amount of the chemical conversion coating film adhered was 100 mg / m ² .

The plating component used in the examples is Zn-11% Al-3% Mg-0.2% Si as described above, but the portion targeted by the present invention is a welded portion, and plating is also performed. The plating type is not limited to Zn-11% Al-3% Mg-0.2% Si because the plating type is characterized by disappearing and the presence of scale. In the examples shown below, in addition to the above galvanized alloy plating, a galvanized steel strip having a pure galvanized layer having an adhesion amount of 140 g / m ² per side is also used for verification.

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

Similarly, a general zinc-based plated steel strip was cut into a flat plate test piece, and a rust preventive film was formed in the same manner as the T-shaped test piece.

When forming the rust preventive film, a paint containing the amounts and metal components shown in Tables 1 and 2 is spray-applied so that the film thickness becomes the values shown in Tables 1 and 2. It was dried. After the formation of the rust preventive film 101, a sample is taken, the thickness T (μm) of the rust preventive film is measured by SEM, and the content M (mass%) of the metal component in the rust preventive film by ICP spectroscopic analysis. Was measured, and I _w was calculated.

When the rust preventive film is composed of a plurality of laminates, after the rust preventive film 1 is formed as described above, the amount and metal component shown in Tables 1 and 2 are similarly contained. The rust preventive film 2 was applied by spraying so that the film thickness became the values shown in Tables 1 and 2, and then dried. Further, in some examples, after the rust preventive film 1 is formed, or after the rust preventive film 1 and the rust preventive film 2 are formed, a coating film layer containing a bright pigment (rust preventive film 3) is used as a color matching coating. Was overcoated. This topcoat coating layer (rust preventive film 3) is an epoxy resin manufactured by Shinto Paint Co., Ltd., which contains about 3% by mass (8.5% by mass in solid content) of flaky aluminum pieces as a bright pigment. It was formed by spray coating with a paint (trade name: Esva (registered trademark) 99 silver) so as to have a film thickness of 15 μm, and then drying.

Corrosion resistance and weldability were evaluated for each sample obtained as described above. The evaluation method is as follows.

(Corrosion resistance)
Corrosion resistance was evaluated by subjecting it to the corrosion test described in JIS H8502 without giving scratches to the rust preventive layer, and those with a red rust generation time of 135 cycles or more were accepted, and Tables 3 and 4 show. Is marked with "○". In addition, those with a red rust generation time of less than 135 cycles were rejected, and "x" is shown in Tables 3 and 4.

(Weldability)
The weldability was evaluated by performing a bead-on test for forming a weld bead on the obtained T-shaped test piece. The welding method was carbon dioxide shield arc welding. As the welding material, NSSW YM28-Z, which is a solid wire for hot-dip galvanized steel sheets manufactured by Nippon Steel & Sumitomo Metal Welding Materials, was used. A wire having a diameter of 1.2 mmφ was used. The heat input was set to 150 A and 20 V, and the test piece was moved at 30 cm / m. The arc torch was tilted 25 degrees from the vertical to have a forward angle. For the T-shaped test piece, an arc weld bead was formed at the position shown in FIGS. 4A and 4B. Further, a weld bead was formed at the position shown in FIG. 5 with respect to the flat plate test piece.

The weldability was evaluated by the flammability of the rust preventive film and the stability of the arc weld bead shape. After welding, disappearance of the rust preventive film and darkening observed over 10 mm or more from the arc welding bead were rejected as flammable, and "x" was shown in Tables 3 and 4. If the arc weld bead was not formed well, the stability was rejected, and "x" is shown in Tables 3 and 4. Those who did not have any problems with respect to the above two items were accepted in the comprehensive evaluation, and "○" was shown in Tables 3 and 4. If even one of the above two items failed, the overall evaluation was rejected.

As is clear from Tables 3 and 4, it was revealed that the sample corresponding to the example of the present invention simultaneously exhibits excellent corrosion resistance and weldability. On the other hand, the sample corresponding to the comparative example could not realize excellent corrosion resistance and weldability.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to 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 steel plate 13 Zinc-based plating layer 15 Bead 101 Anti-corrosion film

Claims (12)

A web made of galvanized steel sheet and
A flange made of galvanized steel sheet and welded to the web,
A weld bead located at a welded portion between the web and the flange,
A rust preventive film that covers at least a part of the weld bead and contains a metal component is provided.
The metal component contains particles having a sacrificial anticorrosive effect on iron.
The content M of the metal component in the rust preventive film is 50 to 98% by mass with respect to the total mass of the rust preventive film.
The Iw represented by the following formula (1) is 19.3 to 30 μm.
The thickness of the rust preventive film is 70 to 130 μm, plated welded shaped steel,
Iw (μm) = T (μm) × (100-M (mass%)) / 100 ... (1)
However, in the formula (1), T is the thickness (μm) of the rust preventive film, and M is the content (mass%) of the metal component in the rust preventive film. The plated welded shaped steel according to claim 1 , wherein the particles having a sacrificial anticorrosion effect are composed of one or both of aluminum and zinc. The plated welded shaped steel according to claim 1 or 2 , wherein the rust preventive film is composed of a zinc rich coating film. At least a part of the rust preventive film
Cover the web with a width of 2 to 25 mm from the boundary between the weld bead and the web along the surface of the web, and from the boundary between the weld bead and the flange toward the widthwise end face of the flange. To cover the flange with a width of 2 to 25 mm.
The plated welded shaped steel according to any one of claims 1 to 3 , which is arranged along the weld bead. At least a part of the rust preventive film
From the boundary between the weld bead and the web along the surface of the web, cover with a width of 2 to 45% of the width of the web, and from the boundary between the weld bead and the flange to the flange. Toward the widthwise end face, cover the flange with a width of 3 to 65% of the distance between the boundary and the widthwise end face of the flange.
The plated welded shaped steel according to any one of claims 1 to 3 , which is arranged along the weld bead. The plated welded shaped steel according to any one of claims 1 to 5 , wherein the rust preventive film is located so as to cover at least a part of the end face of the flange. The rust preventive film is a laminate including a plurality of layers, and is
The plated welded shaped steel according to any one of claims 1 to 6 , wherein at least one of the plurality of layers contains the metal component. The plated welded shaped steel according to claim 7 , wherein at least a part of the outermost layer of the plurality of layers of the rust preventive film is a coating film containing a bright pigment. Further, a zirconium-containing film located on the web and / or the flange and composed of a zirconium element and an organic acid is provided.
The plated welded shaped steel according to any one of claims 1 to 8 , wherein at least a part of the rust preventive film is located on the zirconium-containing film. The plated welded shaped steel according to any one of claims 1 to 9 , wherein the pair of flanges including the flanges are arranged so as to face each other via the web. It is used for welding with additional members and
The plated welded structural steel according to any one of claims 1 to 10 , wherein the rust preventive film is not arranged at a portion to be welded to the flange and / or the member of the web. A plated welded section steel comprising a web made of a zinc-based plated steel plate, a flange made of a zinc-based plated steel plate and welded to the web, and a weld bead formed at a welded portion between the web and the flange. It has a step of coating at least a part of the weld bead with a rust preventive film.
The rust preventive film contains a metal component containing particles having a sacrificial anticorrosive effect on iron.
The content M of the metal component in the rust preventive film is 50 to 98% by mass with respect to the total mass of the rust preventive film.
The Iw represented by the following equation (1) is 19.3 μm to 30 μm.
A method for producing a plated welded section steel, wherein the thickness of the rust preventive film is 70 to 130 μm.
Iw (μm) = T (μm) × (100-M (mass%)) / 100 ... (1)
However, in the formula (1), T is the thickness (μm) of the rust preventive film, and M is the content (mass%) of the metal component in the rust preventive film.