JP2001254192A - Structure and method for corrosion protection by sticking titanium thin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure and a method for corrosion protection of a steel structure in which the application is easy and inexpensive while maintaining the corrosion resistance for a super-long period in the corrosion protection technology of the steel structure. SOLUTION: In the structure and method for corrosion protection by covering the steel surface of the steel structure with a titanium thin sheet, (1) the titanium thin sheet is welded to a metal hanger by the resistance welding after the metal hanger is welded to the steel surface of the steel structure, and (2) the metal hanger welded to the titanium thin sheet is welded to the steel surface of the steel structure after the titanium thin sheet and the metal hanger are welded in advance by the resistance welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a general anticorrosion technique for steel structures such as bridges, steel towers, elevated water tanks, tanks, and marine structures, and more particularly to coating a steel sheet of a steel structure with a titanium sheet. The present invention relates to an anticorrosion structure and an anticorrosion method having improved long-term durability.

[0002]

2. Description of the Related Art Steel structures such as bridges, steel towers, elevated water tanks, tanks, and offshore structures cause red rust, yellow-brown floating rust, and flow rust due to corrosion. As a result, the strength of the structure is reduced due to the decrease in wall thickness, and some anticorrosion measures are required. Conventionally, as a method of preventing corrosion of these structures, a painting method is generally used, and a heavy-duty anticorrosive coating with improved long-term durability is known, but the coating cost is high and the service life is limited. In addition, there is a problem that maintenance cost is high since regular repainting is necessary.

On the other hand, by adding a small amount of elements such as P, Cu, Cr and Ni to steel materials, dense rust (stable rust) having protection against corrosion is formed in the air in several years. Weather resistant steel is known as a steel material having a very low corrosion rate. Since weather-resistant steel is a so-called maintenance-free steel that has a permanent anticorrosive effect without being painted after stable rust is formed, its use in structures such as bridges and steel towers has been increasing in recent years.

However, in places where stable rust is unlikely to be formed, for example, at the end of a bridge girder or under a flange, or in a sea salt particle flying environment or a snowmelt salt spraying area on the coast, unstable rust is generated, so that corrosion prevention is required. It is not preferable because the effect does not appear. Furthermore, there is a problem in that floating rust such as red rust and yellow rust and flowing rust are generated, which causes a problem in appearance and also causes environmental pollution in the surroundings, thereby limiting the usable area.

[0005] Furthermore, since the weather-resistant steel material improves the weather resistance by forming stable rust on the surface, there is also a problem that it is refrained from urban structures that require an aesthetic appearance. Was.

[0006] In order to solve these problems, there is known a method of preventing corrosion of a steel structure by coating a corrosion-resistant surface of the steel structure with a thin sheet of titanium having corrosion resistance. Titanium has high corrosion resistance, and covering the anticorrosion target surface with titanium theoretically enables semi-permanent anticorrosion. As a method of coating titanium on the anticorrosion target surface, a method of welding a titanium thin plate directly to a steel material surface, a method of attaching a titanium thin plate with an adhesive, a structure of attaching a titanium thin plate,
Method of using titanium clad steel over the entire anticorrosion structure (19
The Journal of the Japan Welding Society, Vol. 60, No. 8, No. 38, published in 1991
P.) Are known.

Further, in recent years, cases of using a titanium thin plate as a roof material have increased, and in this case, a method of fixing the titanium thin plate by screwing a suspension member to a roof beam or the like has been adopted. Furthermore, in order to improve the joint strength and water tightness of the joint of the titanium thin plates, the titanium thin plates may be welded to each other by resistance welding (spot welding or seam welding). In this case, a titanium suspension is used. After fixing to the roof beam by screwing, the titanium suspension and the titanium sheet are welded and joined by resistance welding (spot welding or seam welding), and the joint of the titanium sheet is subjected to resistance welding. The method of welding and joining to ensure watertightness has been adopted.

[0008]

However, it is not easy to completely cover the surface of a steel structure with titanium. For example, when a titanium thin plate is directly welded to the surface of a steel material, the welded portion becomes an alloy of titanium and iron, which impairs strength and corrosion resistance. In the method of attaching a titanium sheet with an adhesive, water or a corrosive substance penetrating from a joint or an end of the titanium sheet causes corrosion on the steel surface of the steel structure, which is not suitable for long-term use. The method of using titanium clad steel over the entire anticorrosion structure has a problem that the price is extremely high.

Further, in the method of coating a titanium thin plate using a titanium suspender according to the prior art, it is necessary to make a hole in the structure and screw the titanium suspender. However, it is difficult to screw the structure to a structure because there is a concern about a problem such as a decrease in strength of the structure. further,
It has been difficult to weld-join a titanium suspension with a steel structure because titanium and iron form an alloy and impair strength and corrosion resistance. Furthermore, the titanium sheet can be fixed to the steel structure with an adhesive or adhesive, and watertightness can be ensured by seam welding only at the joints. However, concerns remain over the long-term durability of the adhesive and adhesive. .

Accordingly, the present invention provides an anticorrosion structure and an anticorrosion method for a steel structure, characterized in that it is easy and inexpensive to construct while maintaining an extremely long-term corrosion resistance in a technique for anticorrosion of a steel structure. Aim.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied an anticorrosion structure of a steel structure which can be easily constructed at a lower cost while maintaining an extremely long-term corrosion resistance. Was done.

As a result, in the anticorrosion structure in which the steel surface of the steel structure is covered with the titanium sheet, a metal suspender is arranged between the steel surface and the titanium sheet, and the metal suspender and the titanium sheet are resistance-welded. It has been found that the above problem can be solved by a structure in which the suspension is welded to a steel material.

The present invention has been made based on such knowledge, and is a corrosion protection structure and a corrosion protection method for a steel structure having the following features. [1] In a corrosion prevention structure in which the surface of a steel material of a steel structure is covered with a titanium sheet, a metal suspension is disposed between the steel surface and the titanium sheet, and the metal suspension and the titanium sheet are subjected to resistance welding. A corrosion prevention structure for a steel structure, wherein the metal suspension is welded to a steel material. [2] The anticorrosion structure for a steel structure according to [1], wherein the metal suspender is formed by brazing a metal and a titanium plate. [3] The anticorrosion structure for a steel structure according to the above [1], wherein the metal suspender is obtained by welding a titanium clad material and a titanium plate. [4] In the anticorrosion method of coating a steel surface of a steel structure with a thin titanium plate, a metal suspension is welded to the steel surface of the steel structure by welding, and then the titanium thin plate is resistance-welded to the metal suspension. An anticorrosion method for a steel structure, comprising joining. [5] In the anticorrosion method of coating a steel material surface of a steel structure with a titanium thin plate, the titanium thin plate and a metal suspension are previously joined by resistance welding, and then the titanium thin plate is joined to the steel material surface of the steel structure. A corrosion prevention method for a steel structure, comprising welding a metal suspension element.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a structure in which a steel sheet surface of a steel structure is coated with a titanium sheet to prevent corrosion, comprising a metal suspension between the steel sheet surface of the steel structure and the titanium sheet, The metal suspension and the titanium thin plate are joined by resistance welding, and the metal suspension is welded to steel.

The titanium sheet coated on the steel surface prevents water and corrosive substances from reaching the steel surface. By preventing intrusion of water and corrosive substances, corrosion of the steel material surface is prevented, and the super long-term durability of the steel structure is maintained.

Further, since the titanium thin plate is arranged on the surface of the steel structure via the metal hanging member, the difference in thermal expansion coefficient between the steel material generated due to the temperature difference between the temperature and the titanium thin plate attached thereon is generated. It has the effect of relieving stress and preventing the titanium thin plate from peeling off. Further, even when there is unevenness on the surface of the steel material caused by a weld bead of the steel structure or a step due to a difference in sheet thickness, the construction can be performed, and the effect of improving the external appearance can be obtained. In addition, in the work of attaching a metal sheet, it is sufficient if there is a normal welding equipment and a resistance welding machine,
The construction is easy, the construction speed is high, and the construction can be performed at a lower cost.

Here, an example of the procedure of the anticorrosion structure according to the present invention will be described below. The procedure consists of a pre-treatment step of pre-treatment of the steel surface of the steel structure to be protected against corrosion, a welding step of welding and joining a metal suspender to the surface of the steel material, and further placing a titanium thin plate on the steel sheet and forming a titanium sheet by resistance welding. It can be divided into a resistance welding process for fixing the thin plate and sealing the seam. Hereinafter, details of each step will be described.

Base treatment step Before the metal suspension is welded and joined, a base treatment of the steel material surface of the steel structure is performed. The base treatment of the welded portion of the metal suspender is performed using a disk grinder or the like until the steel material surface is exposed. In addition, as a base treatment other than a welding portion where a metal suspender is welded, the following treatment is performed on a new steel structure or an existing steel structure.

[In the case of a new steel structure] Blast treatment (equivalent to ISO Sa2.5 or ISO Sa3), polishing (smooth surface) treatment, primer coating (inorganic zinc-rich primer, etc.) with black scale (steel plate with mill scale) as it is Primer) treatment, painting (including rust prevention coating) treatment.

Incidentally, these treatment methods may be carried out alone or in combination of two or more kinds.

[In case of existing steel structure] Blasting treatment (I
SO Sa2.5 or ISO Sa3), 2 types of Keren (equivalent to ISO St3) treatment, 2 types of Keren (ISO
St3 equivalent) + Painting (including rust-proof coating)

It should be noted that these processing methods may be performed alone or in combination of two or more.

Metal Suspension Welding Step The metal suspension is welded to the surface of the steel material which has been subjected to the base treatment.

The material of the metal suspender is not particularly limited as long as it is a metal that can be welded to a steel material and a metal that can be welded and joined to a titanium thin plate by a resistance welding method. And the like, nickel, nickel alloy, titanium clad steel, and the like. Note that stainless steel is particularly preferable because it is relatively inexpensive and easily available, and is excellent in corrosion resistance even if the plate is thin. As the type of stainless steel, for example, SUS304, SUS
316 and the like.

Further, a material obtained by joining the above metal and a titanium plate can also be used. That is, the metal and the titanium plate are joined by a method such as riveting, welding, or brazing, the metal portion is welded to a steel material, and the titanium plate portion is joined to the titanium thin plate for coating by a resistance welding method.

When the metal and the titanium plate are joined by riveting to produce a metal suspension, the material of the rivet may be stainless steel, iron, copper, brass, aluminum or the like, and is not particularly limited. Note that stainless steel is preferable as the metal to be bonded to the titanium thin plate. This is because stainless steel is relatively inexpensive and easily available, and has excellent corrosion resistance even when the plate thickness is small. As the type of stainless steel, for example, SU
S304, SUS316 and the like.

When the metal and the titanium plate are joined by a welding method to produce a metal suspension, the welding may be spotted, may be performed on the entire circumference or partially, and may be a method that can sufficiently secure the joining strength. It is not particularly limited. As the welding method, a normal welding method may be used, for example, resistance welding (spot welding, seam welding, etc.), arc welding (covered arc welding, gas shielded arc welding, etc.), gas welding, laser welding, etc. be able to. It is preferable to use titanium clad steel as the metal to be bonded to the titanium plate. This is because titanium as a composite material of titanium clad steel and a titanium plate can be strongly bonded.

When a metal suspension is manufactured by joining the metal and the titanium plate by brazing, a metal / alloy (brazing) having a melting point lower than that of the base material is applied to the joint between the metal and the titanium plate outside the joint. , And are allowed to penetrate into the joint gap by wetting and capillary phenomenon to join. The types of brazing materials include copper brazing, brass brazing, silver brazing, phosphor bronze brazing, gold brazing,
There are palladium brazing, nickel brazing, aluminum brazing and titanium brazing. Among them, the type of the brazing material for titanium brazing is silver brazing (Ag-Cu based, Ag-Cu based).
-Ni-based, Ag-Al-based), aluminum brazing (pure Al, Al-Mn-based, etc.), titanium brazing (Ti-Ni-
Cu-based, Ti-Zr-Ni-Cu-based, and zirconium brazing (Zr-Cu-based) are preferred. Also,
Stainless steel is preferable as the metal to be bonded to the titanium plate. This is because stainless steel is relatively inexpensive and easily available, and has excellent corrosion resistance even when the plate thickness is small. Examples of the type of stainless steel include SUS304 and SUS316.

The metal and the titanium plate may have a structure that does not easily separate from each other, and the titanium plate may have a movable structure. By using a movable suspension, the stress caused by the difference in the coefficient of thermal expansion between the steel sheet generated by the temperature difference between the temperature and the titanium sheet to be stuck thereon is reduced, and the distortion of the titanium sheet caused by seam welding is reduced. It also has a moderating effect. This alleviates the stress applied to the metal suspension and has an effect of preventing the titanium thin plate from peeling off.

The thickness of the metal suspension is 0.05 to 5
mm is preferable, and the range of 0.2 to 0.5 mm is more preferable. If the plate thickness is smaller than 0.05 mm, the strength is weak. If the plate thickness is larger than 5 mm, not only the processing becomes difficult, but also the watertightness cannot be maintained at the steps due to the difference in the plate thickness in the resistance welding process. Because.

When a steel material, a weldable metal and a titanium plate are used in combination, the thickness of the titanium plate is set to 0.1.
The range of 05 to 5 mm is preferable, and the range of 0.1 to 0.4 mm is more preferable. If the plate thickness is smaller than 0.05 mm, the strength is weak. If the plate thickness is larger than 5 mm, not only the processing becomes difficult, but also the watertightness cannot be maintained at the steps due to the difference in the plate thickness in the resistance welding process. Because. The thickness of the metal that can be welded to steel is 0.1 to 10
The range of mm is preferable, and the range of 1 to 5 mm is more preferable. If the plate thickness is less than 0.1 mm, the strength is weak, and welding with a steel material becomes difficult. If the plate thickness is more than 10 mm, not only processing becomes difficult, but also the weight of the suspender itself becomes heavy and workability deteriorates.

FIGS. 1 and 2 show an example of the shape of a metal suspender. FIG. 1 shows an example of a fixed type suspender, and FIG. 2 shows an example of a movable type suspender. 1 and 2, 3 indicates a spot weld or riveted portion, 4 indicates a seam weld, 5 indicates a spot weld, and 12 indicates a braze.

In FIG. 1, (a) is a plate-shaped suspender made of a metal plate 1 which can be welded to a steel material and which can be welded to a thin titanium plate by a resistance welding method.
And (c) to (j) are perspective views of the suspender in which the metal plate 1 and the titanium plate 2 are joined. (C) is a plate-shaped metal plate 1 on which an L-shaped titanium plate 2 is placed and joined by spot welding or riveting, and (d) is a plate-shaped metal plate 1 Section L
FIG. 5E shows a state in which a T-shaped titanium plate 2 is placed and joined by seam welding, and FIG.
A titanium plate 2 having an L-shaped cross section is passed therethrough and joined by spot welding or riveting, and (f) shows a slit-shaped hole 20 formed in the plate-shaped metal plate 1 and an L-shaped cross section is formed there. (G) a titanium plate 2 having an L-shaped cross section placed on the plate-shaped metal plate 1 and brazed to the metal plate 1;
(H) is a plate-shaped metal plate 1 in which a slit-shaped hole 20 is opened and a titanium plate 2 having an L-shaped cross section is passed therethrough and brazed to the metal plate 1, and (i) is a metal plate 1 Is a titanium clad material 16, a titanium plate 2 having an L-shaped cross section is placed on a titanium 17 as a bonding material, and the titanium plate 17 is bonded to the titanium 17 as a bonding material by spot welding.
Is a titanium clad material 16, and a titanium plate 2 having an L-shaped cross section is placed on a titanium 17 as a bonding material, and the titanium with the bonding material is joined by seam welding. The titanium clad material 16 used in (i) and (j) is used.
The titanium 17 of the composite material may be pure titanium or a titanium alloy, and the base material 18 may be any of ordinary steel or alloy steel. The thickness of the titanium 17 of the titanium clad material 16 is 0.1 to 5 mm, and the thickness of the base material 18 is 1 to 10 m.
m, the cut-back amount M of titanium as a composite material is 1 to 10 m
m is preferable.

FIG. 2 is a perspective view of the movable suspension. This movable suspension is a metal plate which can be welded to the steel material shown in FIGS. 1 (c) to 1 (f). In this suspension, the titanium plate 2 can be moved in the direction of the arrow by adopting a structure as shown in FIG.

FIG. 3 is a diagram showing an example of a method of welding a metal suspension and a steel material. (A) is a method of welding the outer periphery of the metal suspender 15 to the steel surface 9; (b) and (c) are making holes 6 and slits 7 in the metal suspender 15 and welding to the steel surface 9 at that portion. How to Needless to say, the shapes of the holes and slits are not limited to those shown in the drawings. Further, the welding of (a) may be spotted or performed on the entire circumference or a part thereof, and is not particularly limited as long as the bonding strength between the steel material and the suspender can be sufficiently secured. In addition, as a welding method, a normal welding method may be used, and for example, arc welding (covered arc welding, gas shielded arc welding, etc.), gas welding, laser welding, or the like can be used. Here, FIG. 3 illustrates only the metal suspension having an L-shaped cross section, but the suspensions of all shapes illustrated in FIGS. 1 and 2 can be welded in the same manner.

After the metal suspension is welded to the surface of the steel material, a waterproof sheet is attached to the surface of the steel material and the surface of the metal suspension other than the portion to be resistance-welded to the titanium plate using an adhesive or an adhesive tape. May be attached. The tarpaulin is
The waterproof property prevents water and corrosive substances from penetrating into the surface of the steel material, thereby preventing the corrosion of the steel material surface. In addition, it has the effect of buffering irregularities on the surface of steel materials such as weld beads of steel structures and steps due to thickness differences, and the effect of improving the workability and improving the appearance of the titanium sheet coated on it. Have.

The main material of the waterproof sheet is a rubber material such as unvulcanized or vulcanized butyl rubber, acrylic, epoxy, Teflon (registered trademark), silicon,
A resin material such as olefin, α-olefin, urethane, or a combination thereof is preferable. Particularly preferred is unvulcanized butyl rubber in view of its price, water tightness, stress relaxation effect and the like.

As the waterproof properties of the waterproof sheet, it is preferable that the water absorption rate is 1.0% or less and the volume resistivity as the electrical insulation is 10 ⁶ Ω · cm or more.

Further, the form of the waterproof sheet may be a rubber material or a resin material alone, but it may be a multi-layer formed by combining them with a foamed layer having closed cells or a layer having a cushioning property such as a nonwoven fabric or a mesh. It can also be a sheet. By using a multilayer sheet, the effect of buffering steps on the surface of the steel material is improved.

The thickness of the waterproof sheet is preferably from 0.1 to 5 mm. If it is less than 0.1 mm, it is easily broken and there is a problem in waterproofness and workability. If it is more than 5 mm, it becomes too heavy to handle. Particularly preferred one is 0.5 to 2 mm.

Examples of the method for attaching the waterproof sheet include a method using an adhesive, a method using an adhesive, a method using a combination of an adhesive and an adhesive, and an adhesive sheet in which a substrate is impregnated or coated with an adhesive. Alternatively, there is a method using an adhesive tape. Further, a waterproof sheet having an adhesive surface may be used.

The adhesive is not particularly limited, but may be vinyl acetate, acrylic, ethylene, polyamide, polyimide, polyvinyl alcohol, polyester, polyurethane, urea, melanin, phenol, resorcinol,
Epoxy, polyimide, natural rubber, chloroprene rubber,
Resin such as nitrile rubber, urethane rubber, styrene-butadiene rubber, butyl rubber, α-olefin, cyanoacrylate, modified acrylic, or a combination thereof, as the main material, solvent drying type, two-component mixing reaction type, catalyst addition type It is preferable to use one that is cured by a curing method such as a moisture curing type, an anaerobic curing type, a thermosetting type, a hot melt type, a pressure sensitive type, and a rewetting type.

The adhesive is preferably made of a polyamide, polyimide, epoxy or cyanoacrylate resin as a main material from the viewpoint of adhesiveness to metal.

The thickness of the adhesive is not particularly limited, but is preferably 0.05 to 1.0 mm in order to avoid poor adhesion due to a thin film, an increase in internal stress due to a thick film, and an increase in factors of peeling.

As the pressure-sensitive adhesive, it is convenient to use a tape-shaped or sheet-shaped substrate impregnated with or coated with a pressure-sensitive adhesive. Rubber or resin can be used as the base material. The adhesive tape may be used only at the end of the waterproof sheet, or the adhesive tape may be used only at the end of the waterproof sheet and an adhesive may be used at other portions.

Here, the pressure-sensitive adhesive tape is one obtained by applying a pressure-sensitive adhesive to the surface of a tape base material or formed integrally, and is preferably a material having high adhesion strength to the steel material surface and the waterproof sheet. For example, as a base material of the adhesive tape, a rubber material such as butyl rubber, acrylic, silicon,
A resin material such as ethylene or epoxy, or a combination thereof can be used as the material. As the adhesive, natural rubber, styrene-butadiene rubber, butyl rubber, acrylic, or the like can be used. The thickness of the adhesive tape is 0.5 to 2.0 mm, and the adhesive strength is 1 k.
g / cm or more is preferred.

Resistance Welding Step By the resistance welding method, the metal suspension and the titanium thin plate are joined and the joint between the titanium thin plates is sealed, and the steel material surface is covered with the titanium thin plate. The joining of the titanium sheet and the metal suspension may be performed by spot welding or seam welding.
Seam welding may be performed after temporarily fixing by spot welding. The joining of the joints between the titanium thin plates may be performed by spot welding or seam welding. In general, it is preferable to use seam welding from the viewpoint of workability and continuity, but spot welding is used in a portion where seam welding is difficult such as a corner. May be used continuously. Further, the fixing of the titanium thin plate and the metal suspender may be temporarily fixed by spot welding, and seam welding may be performed collectively when sealing the joint between the titanium thin plates.

The thickness of the titanium sheet for coating is 10 μm to 1 μm.
mm is preferable. When the thickness is less than 10 μm, the thin plate is easily broken at the time of construction. If the thickness is more than 1 mm, the weight of the thin plate itself increases, and the workability deteriorates, and the cost increases. Incidentally, particularly preferred ones are
It is about 50 μm to 400 μm.

It is also preferable that the flat portion of the titanium thin plate is processed to have a wavy shape. This is because not only can a stress caused by a difference in thermal expansion coefficient between a steel material generated due to a temperature difference in temperature and a titanium thin plate mounted thereon be reduced, but also an effect of alleviating a strain generated by seam welding.

FIG. 4 is a view showing an example of a joining method of a joint portion for joining thin titanium plates. The joining method of the joint portion of the titanium thin plate is not limited to the method shown in FIG. 4 as long as it can prevent water and corrosive substances from entering. 4, reference numeral 4 denotes a seam weld, 5 denotes a spot weld, and 8 denotes a weld between the metal suspension and the surface of the steel material.

(A) A metal suspender 15 having an L-shaped cross section in advance
Is welded to the surface 9 of a steel material and the end of the titanium sheet 1 is bent.
After disposing the bent portion of 0 so as to be parallel to the standing plate of the metal suspender 15 and temporarily fixing it by spot welding, the end of the metal suspender 15 was further bent from the opposite side of the standing plate. The bent portion of the titanium thin plate 11 is covered so as to cover the standing plate of the metal hanging member 15 and the bent portion of the titanium thin plate 10, and the standing portion of the metal hanging member 15, the bent portion of the titanium thin plate 10, and After temporarily fixing the overlapping portion of the bent portion of the titanium thin plate 11 by spot welding,
Join by seam welding.

(B) In (a), the bent portion of the titanium thin plate 10 is made longer than the standing plate of the metal suspender 15, and the titanium thin plates are spot-welded to each other at the overlapping portion of the titanium thin plates 10 and 11 by spot welding. Later, the metal suspension 1
The overlapping portions of the standing plate 5, the bent portion of the titanium thin plate 10 and the bent portion of the titanium thin plate 11 are joined by seam welding.

(C) and (b), the standing plate of the metal suspension 15, the bent portion of the titanium thin plate 10 and the titanium thin plate 11
The overlapping portions of the bent portions are fixed by spot welding, and the titanium thin plates are joined to each other at the overlapping portions of the titanium thin plates 10 and 11 by seam welding.

(D) The plate-shaped metal suspender 15 and the titanium sheet 10 whose end is bent are joined in advance by seam welding, and the metal suspender 15 and the steel material surface 9 are welded. Then, the bent portion of the titanium thin plate 11 whose end is bent is covered so as to cover the bent portion of the titanium thin plate 10, and the titanium thin plates are joined to each other by seam welding at the overlapping portion of the titanium thin plates 10, 11.

(E) After the plate-shaped metal suspender 15 and the thin titanium plate 10 whose end is bent are joined in advance by spot welding, the metal suspender 15 and the steel material surface 9 are welded. Then, the bent portion of the titanium thin plate 11 whose end is bent is covered so as to cover the bent portion of the titanium thin plate 10, and the titanium thin plates are joined to each other by seam welding at the overlapping portion of the titanium thin plates 10, 11.

In FIGS. 4A to 4C, the cross section L
1 (c) to 1 (j) in place of the letter-shaped metal suspension 15
It is also possible to use a suspension having the shape shown in FIGS. 2 (a) and 2 (c). In this case, since the upright portion of the metal suspender 15 having an L-shaped cross section in FIGS. 4A to 4C is made of titanium, the joining with the thin titanium sheet for covering becomes the joining between titanium and more firm. It is preferable because it becomes a junction.

Here, in the case of spot welding, welding may be performed after bonding the joints with an adhesive in advance. It should be noted that a joining method in which a non-joined portion exists is not appropriate because water leaks from the non-joined portion.

FIG. 5 is a view showing a treatment method when the seams of the titanium thin plates cross. The rising portion (joining portion) of the end of the previously welded titanium sheet joint is folded down so as to be folded into any of the titanium sheet sides, and then the ends of the welding portions are respectively set in the same manner as in the joining method in FIG. Raise and stack, and perform seam welding. In addition, it is not necessary to perform the convolution on all of the rising portions welded earlier,
Next, it may be applied only to the vicinity of the location to be welded.
At this time, if the intersecting portion is too thick, it is difficult to secure water tightness at the intersecting portion. Therefore, it is preferable not to dispose the suspender near the intersecting portion.

The arrangement method of the metal suspenders is as follows.
Suspensions having a length of about 2 to 10 cm may be arranged at equal intervals, or suspensions having the same length as the joint length of the titanium thin plate may be used.

FIG. 6 is a diagram showing an example of a method for treating the end of a titanium thin plate. Thereby, permeation of water or the like from the end can be more reliably prevented, and the durability is further improved. The treatment method at the end of the titanium thin plate is not limited to the method shown in FIG. 6 as long as it can prevent water or corrosive substances from entering. In FIG. 6, 4 denotes a seam weld, 5 denotes a spot weld, and 8 denotes a weld between the metal suspension and the steel surface.

(A) The plate-shaped metal suspender 15 is previously joined to the titanium thin plate 10 by seam welding, and then the metal suspender 15 is welded to the steel surface 9 to ensure watertightness.

(B) A plate-shaped metal suspender 15 is joined to the end of the titanium thin plate 10 by seam welding in advance, and then the metal suspender 15 is welded to the steel material surface 9 to ensure watertightness.

(C) The bent portion of the titanium sheet 10 whose end is bent is covered so as to be covered with an upright portion of a metal suspender 15 having an L-shaped cross section, and the bent portion of the titanium sheet 10 and the metal After joining the overlapping portions of the standing plates of the suspension 15 by seam welding, the metal suspension 15 is welded to the steel surface 9. Here, after the metal suspension 15 is welded to the steel surface 9 in advance, the titanium sheet 10 and the metal suspension 1 are welded.
5 may be joined.

(D) The upright portion of the metal suspender 15 having an L-shaped cross section is covered so as to cover the bent portion of the titanium thin plate 10 whose end is bent, and the bent portion of the titanium thin plate 10 and the metal After joining the overlapping portions of the standing plates of the suspension 15 by seam welding, the metal suspension 15 is welded to the steel surface 9. Here, after the metal suspension 15 is welded to the steel surface 9 in advance, the titanium sheet 10 and the metal suspension 1 are welded.
5 may be joined.

In FIGS. 6 (c) and 6 (d), instead of the metal suspender 15 having an L-shaped cross section, FIGS.
It is also possible to use a suspension having the shape shown in FIG. 2 (j) and FIGS. 2 (a) and 2 (c). In this case, since the upright portion of the metal suspender 15 having the L-shaped cross section in FIGS. 6C and 6D is made of titanium, the joining with the thin titanium plate for covering becomes the joining between titanium, and is more robust. It is preferable because it becomes a junction.

As described above, there is provided an anticorrosion structure for a steel structure which can be easily and inexpensively constructed while maintaining an extremely long-term corrosion resistance. Further, an anticorrosion method according to the present invention is provided.

The present invention may be applied to the construction of a new steel structure or to the repair of an existing steel structure.

[0068]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

As an example of the present invention, a test material provided with a joint between thin titanium plates was prepared. Table 1 shows processing methods according to Examples 1 to 10 and Comparative Examples 1 and 2 of the present invention.

[0070]

[Table 1]

As the test steel, a normal steel (500 mm
× 500 mm × 6 mm).

In Examples 1 to 6 and Comparative Example 2, the suspension was welded to the surface of the steel material by the coated arc welding method, the titanium sheet was arranged and temporarily fixed by the spot welding method, and then the titanium sheet was welded by the seam welding method. The entire seam was joined. In Examples 7 to 10, a metal suspension was seam-welded to one end of one titanium thin plate in advance, and then the suspension was joined to the surface of the steel material by covered arc welding. Then, the other titanium thin plate was arranged and temporarily fixed by spot welding, and then the entire joint of the titanium thin plate was joined by seam welding. In Comparative Example 1, a titanium thin plate was fixed only with an adhesive without using a suspender.

Here, the conditions for spot welding are as follows. Electrode tip diameter: 3mm Energizing time: 5 cycles (50Hz) Pressure: 80kgf Welding current: 3kA

The conditions for seam welding are as follows. Electrode tip width: 4mm Welding speed: 3m / min Pressing force: 120kgf Energizing time: 5 cycles energization-1 cycle no energization (50H
z) Welding current: 3.5 kA

Examples 1 to 10 obtained as described above
The test pieces of Comparative Examples 1 and 2 were subjected to a test for verifying long-term durability. In the test, a test piece was repeatedly irradiated with ultraviolet light, rainfall, and salt fly using a combined cycle accelerated weathering test apparatus. Specimens were evaluated after a period corresponding to 20 years of exposure in an environment near the shore. As the evaluation method, the appearance was examined, the presence or absence of peeling of the metal sheet, the metal sheet was forcibly peeled, and the appearance of the steel surface under the metal sheet was examined.

In Examples 1 to 10, the titanium sheet was not peeled off, the watertightness of the joint was maintained, and no corrosion was observed on the steel material surface. On the other hand, in Comparative Example 1, peeling of the titanium sheet was observed from the seam, and further, corrosion of the steel material surface was observed. In Comparative Example 2, the seam was kept watertight, but the titanium suspension and the weld on the steel surface were easily separated.

[0077]

As described above, according to the present invention, there is provided an anticorrosion structure and an anticorrosion method for a steel structure which can be easily and inexpensively constructed while maintaining ultra-long-term corrosion resistance by minimum maintenance.

The present invention may be applied to the construction of a new steel structure, or may be applied to the repair of an existing steel structure.

[Brief description of the drawings]

FIG. 1 is a view showing an example of the shape of a fixed suspension element.

FIG. 2 is a diagram showing an example of the shape of a movable suspension element.

FIG. 3 is a diagram showing an example of a method of welding a suspension and a steel material.

FIG. 4 is a diagram showing an example of a joining method of a joint portion for joining titanium thin plates.

FIG. 5 is a view showing an example of a treatment method in a case where seams of titanium thin plates intersect.

FIG. 6 is a view showing an example of a method for processing an end portion of a titanium thin plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Metal plate which can be welded with a steel material and which can be welded and joined to a titanium thin plate by a resistance welding method 2 Titanium plate 3 Spot welding or riveted portion 4 Seam welded portion 5 Spot welded portion 6 Hole 7 Slit 8 Welded portion 9 Steel material surface 10, 11 Titanium thin plate 12 Brazing part 15 Metal suspension 16 Titanium clad material 17 Titanium (combined material) 18 Base material 20 Slit hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23K 103: 14 B23K 103: 14

Claims (5)

[Claims] In a corrosion-resistant structure in which a steel material surface of a steel structure is covered with a titanium sheet, a metal suspension is arranged between the steel surface and the titanium sheet, and a resistance is provided between the metal suspension and the titanium sheet. A corrosion prevention structure for a steel structure, wherein the structure is welded and the metal suspension is welded to a steel material. 2. The anticorrosion structure for a steel structure according to claim 1, wherein the metal suspension is formed by brazing a metal and a titanium plate. 3. The anticorrosion structure for a steel structure according to claim 1, wherein the metal suspension is formed by welding a titanium clad material and a titanium plate. 4. A corrosion prevention method for covering a steel material surface of a steel structure with a thin titanium plate, wherein a metal suspension is welded to the steel material surface of the steel structure, and then the titanium thin plate is resistance-welded to the metal suspension. Corrosion protection method for steel structures, characterized in that they are joined with each other. 5. A corrosion prevention method for covering the surface of a steel material of a steel structure with a thin titanium plate, wherein the titanium thin plate and a metal suspension are previously joined by resistance welding, and then the titanium thin plate is joined to the steel material surface of the steel structure. A method for preventing corrosion of a steel structure, comprising welding the above-mentioned metal suspender by welding.