JPH1058031A - Manufacture of steel tube having double corrosion-resisting metallic coating layers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of efficiently and inexpensively forming an intermediate resin layer and a surface coating layer of a corrosion-resistant metal plate on the surface of a steel pipe and manufacturing a corrosion-resistant metal-coated multi-layer steel pipe in a simple process. . SOLUTION: A block material for maintaining a gap is joined to a surface of one side of a strip-shaped corrosion-resistant metal plate at a plurality of places, and the block material is brought into contact with the surface of a steel pipe to wind the corrosion-resistant metal plate spirally around the outer periphery of the steel pipe. A curable resin or a thermoplastic resin is injected into a gap between the plate and the surface of the steel pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multi-layer coated steel pipe having excellent corrosion resistance, which is used in a tidal spray zone of an offshore structure.

[0002]

2. Description of the Related Art Conventionally, for example, anticorrosion steel pipes or anticorrosion steel pipe piles used in the ocean are coated or coated with polyethylene,
Some are made of urethane-based heavy duty corrosion protection. However, the corrosion resistance of these steel pipes is limited, and the life is one in the case of painting.
About 20 years, about 40 years for heavy corrosion protection. Further, there is a steel pipe using stainless steel or clad steel in order to enhance the corrosion resistance of the corrosion-resistant steel pipe. In the case of this steel pipe, the initial cost is high.

As an anticorrosion steel pipe pile, Japanese Patent Laid-Open No. 2-25
As disclosed in Japanese Patent No. 6713, there has been proposed a steel pipe pile having an outer surface coated with an adhesive resin having corrosion resistance and elasticity, and further coated with a corrosion-resistant metal sheet having embossed irregularities.

However, in the case of this corrosion-resistant steel pipe pile, it is necessary to prepare a corrosion-resistant metal plate corresponding to the diameter of the steel pipe to be coated and the coating length, and the productivity is not high. Furthermore, when coating a large-diameter and long steel pipe, a plurality of joints occur in the circumferential direction of the steel pipe of the coated corrosion-resistant metal, and it is difficult to efficiently cover the steel pipe.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-100527 discloses that a steel pipe is coated directly or in advance with an adhesive resin on its surface, a corrosion-resistant metal plate is spirally wound around the outer periphery thereof, and the edges of the metal plate are joined together. Disclosed is a corrosion resistant metal coated steel pipe.

Providing an intermediate resin layer under the corrosion-resistant metal coating is extremely important for ensuring a buffering action for preventing the corrosion-resistant metal sheet from being damaged by impact and a water-proof property on the surface of the steel pipe.

However, when a multi-layer coated steel pipe is manufactured by the above-described method, a step of forming an intermediate resin layer on the surface of the steel pipe and a step of coating a corrosion-resistant metal plate are required, which complicates the manufacturing process. . Further, there is a problem that the life is inevitably reduced because the adhesiveness between the adhesive resin layer and the metal plate is not always sufficient.

[0008]

An object of the present invention is to form an intermediate resin layer as an impact buffer layer and a surface coating layer of a corrosion-resistant metal plate on the surface of a steel pipe efficiently and at low cost, and to form a multi-layer coated steel pipe by a simple process. It is intended to provide a method that can be manufactured.

Another object of the present invention is to provide a method of manufacturing a multi-layer coated steel pipe in which the thickness of the intermediate resin layer is made uniform and the corrosion-resistant metal plate is less likely to be deformed by external forces such as waves.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist thereof is as follows: (1) A multilayer coating having an intermediate resin layer and a corrosion-resistant metal coating on the outer periphery of a steel pipe. When manufacturing steel pipes, a block material for maintaining a gap is joined to a plurality of locations on one surface of a corrosion-resistant metal plate,
Corrosion resistance characterized in that the block material is brought into contact with the surface of the steel pipe and the corrosion-resistant metal sheet is spirally wound around the outer periphery of the steel pipe, and a hardening resin or a thermoplastic resin is injected into a gap between the corrosion-resistant metal sheet and the surface of the steel pipe. This is a method for producing a metal-coated multilayer steel pipe.

(2) The corrosion-resistant metal plate is made of titanium or an alloy thereof, and titanium or titanium clad steel is used as the block material, and the titanium surface is welded to the surface of the corrosion-resistant metal plate. A method for producing a corrosion-resistant metal-coated multilayer steel pipe according to the above item (1).

(3) Further, the block material is made of a curable resin or a thermoplastic resin, and the block material is joined to the surface of the corrosion-resistant metal plate. This is a method for manufacturing a layered steel pipe.

[0013]

FIG. 1 is a view showing an example of the structure of a corrosion-resistant metal-coated multi-layer steel pipe manufactured by the method of the present invention. On one side (inside) of the corrosion-resistant metal plate 1, a large number of block members 2 for maintaining a gap are joined at predetermined intervals. The block material 2 is brought into contact with the surface of the steel pipe 3 to form the corrosion-resistant metal plate 1.
Is spirally wound around the outer periphery of the steel pipe 3.
A gap having a predetermined thickness is formed between the corrosion-resistant metal plate 1 and the steel pipe 3 by the block material 2, and a resin is injected into the gap to form an intermediate resin layer 4.

The corrosion-resistant metal plate 1 used in the present invention is a thin plate made of titanium, a titanium alloy, stainless steel or the like. Titanium or its alloy is preferable from the viewpoint of corrosion resistance to seawater, and the plate thickness is 0.2. It is about 1.6 mm.

The block material 2 for maintaining the gap may be any material that can be easily manufactured and can be easily joined to the corrosion-resistant metal plate 1.
Metal or resin is suitable. The block material 2 preferably has a uniform thickness, and can be manufactured by punching, cutting out, or the like from a plate-like material.

The thickness thereof is selected according to the required thickness of the intermediate resin layer 4, but is usually about 2 to 8 mm. There is no particular restriction on the cross-sectional shape of the block material, but if a square material is used, irregularities will occur on the surface of the corrosion-resistant metal plate,
Those having a rounded shape are preferred.

FIG. 2 is an explanatory view showing an example of a method for producing a corrosion-resistant metal-coated multilayer steel pipe according to the present invention. The steel pipe 3 is moved in the direction of arrow B at a predetermined speed while rotating in the direction of arrow A. The belt-shaped corrosion-resistant metal plate 1 is unwound from the coil 5,
A plurality of block members 2 are joined to the upper surface by a joining device 6. In order to simplify the operation, it is preferable to simultaneously join a required number of block members over the entire width of the metal plate at multiple points.

In this manner, the corrosion-resistant metal plate 1 to which the block members 2 are joined at predetermined intervals is replaced by the block members 2 and the steel pipes 3.
And wound in a spiral shape. At this time, the pressurizing roll 7 and the pinch roll 8 wind the corrosion-resistant metal plate 1 while applying a constant tightening force.

At the same time, the edges of the corrosion-resistant metal plate 1 are overlapped with each other, and the edges are welded by the welding machine 9. In addition, the joining of the edges of the corrosion-resistant metal plate 1 can be performed by a bonding method using an adhesive or a crimping method in addition to the welding method.

After the metal coating is formed over the entire length of the steel pipe 3 as described above, a resin is injected into a gap formed by the block material 2. FIG. 3 is an explanatory diagram illustrating an example of a method of injecting a resin. Since an excess winding margin (not shown) of the corrosion-resistant metal plate 1 is generated at both ends of the steel pipe 3, this is first cut and shaped.

Next, at both ends of the steel pipe 3, a plastic filler 10 is filled in the gap between the steel pipe 3 and the corrosion-resistant metal plate 1, and the end is sealed. As a method of sealing the end portion, a method of inserting a resilient sealing ring, a method of using an adhesive tape, or the like can also be applied.

After sealing both ends, the resin tank 1 is injected through an injection pump 12 through an injection port 11 provided on the corrosion-resistant metal plate side.
3. Press-fit the resin in 3. The press-fitted resin flows through the gap formed by the gap holding block material 2 and forms an intermediate resin layer over the entire surface of the steel pipe 3. In addition,
The resin injection port 11 may be plural, or may be provided on the steel pipe side.

The resin used in the present invention may be any resin that has a certain degree of fluidity in the resin tank 13 and is hardened by being adhered to the steel pipe 3 and the corrosion-resistant metal plate 1 after being injected. A wide range of curable resins or thermoplastic resins can be used, but for example, polyethylene-based, vinyl chloride-based, urethane-based, epoxy-based, and polyester-based resins are suitable from the viewpoint of seawater resistance.

In the method of manufacturing a corrosion-resistant metal-coated multi-layer steel pipe according to the present invention, it is desirable to be able to simultaneously join a large number of blocks to a strip-shaped corrosion-resistant metal plate in a short time in order to simplify the operation.

The metal block material has high strength and low production cost, and has the advantage that a large number of block materials can be simultaneously joined to a metal plate by spot welding. However, when the block material and the corrosion-resistant metal plate are dissimilar metals, there is a problem that cracks occur at the welded portions.

Therefore, in one joining method of the block material according to the present invention, the corrosion-resistant metal plate is made of titanium or an alloy thereof, and titanium or titanium clad steel is used as the block material, and the titanium surface is attached to the surface of the corrosion-resistant metal plate. It is characterized by welding. With this configuration, the block material can be welded without causing cracks in the welded portion.

Another joining method of the block material according to the present invention is characterized in that the block material is made of a curable resin or a thermoplastic resin, and the block material is joined to the surface of the corrosion-resistant metal plate. In the case of a thermoplastic resin, it is possible to perform hot-melt joining, and in joining, a method in which an end surface of a block material, a corrosion-resistant metal plate, or both are heated and bonded in advance can be applied. As the hard thermoplastic resin, for example, a polyethylene resin can be used.

As the curable resin, urethane-based, polyester-based, epoxy-based resins and the like can be used. As a joining method, for example, the joining can be performed using a quick-drying adhesive.

[0029]

EXAMPLE A corrosion-resistant metal-coated multi-layer steel pipe was manufactured by the method shown in FIGS. The outer diameter of the steel pipe is 800
mm, a pure titanium plate having a width of 400 mm and a thickness of 0.4 mm was used as a corrosion-resistant metal plate.

As the block material, a cylinder of titanium clad steel having a diameter of 5 mm and a thickness of 5 mm was used, and the titanium surface was welded to the titanium plate. The block materials were arranged at equal intervals at a pitch of 20 mm, and the area occupancy on the surface of the titanium plate was about 5%. The titanium plate was spirally wound around the outer periphery of the steel pipe, and at the same time, the edges of the titanium plate were overlapped by about 30 mm, and the edges were joined by seam welding.

The excess winding margin is cut at both ends of the steel pipe having the titanium coating formed in a spiral shape in this manner, and at both ends of the steel pipe, a gap between the steel pipe and the corrosion-resistant metal plate is filled with a plastic resin to seal the end. After stopping, urethane resin was injected into the gap between the steel pipe and the titanium coating by a method as shown in FIG. 3 to form an intermediate resin layer.

According to the method of this embodiment, a steel pipe 1 having a length of 7 m
The work time for covering the book was about 25 minutes, the covering work was simplified, and the manufacturing cost was greatly reduced.

Further, the corrosion-resistant metal-coated multi-layer steel pipe manufactured by the method of this embodiment has a uniform thickness of the intermediate resin layer.
And it was confirmed that the adhesiveness was good and that it could withstand long-term use as a marine structure.

[0034]

According to the present invention, it has become possible to efficiently manufacture a corrosion-resistant metal-coated multi-layer steel pipe by a simple process. In particular, it became possible to form a multilayer coating with the same apparatus and method irrespective of the size of the steel pipe, thereby enabling a significant reduction in manufacturing costs.

Further, the corrosion-resistant metal-coated double-walled steel pipe manufactured by the method of the present invention has a uniform intermediate resin layer and a good adhesion, so that a highly reliable product can be stably manufactured. Was.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structural example of a corrosion-resistant metal-coated multi-layer steel pipe manufactured by a method of the present invention.

FIG. 2 is an explanatory view showing an example of a method for producing a corrosion-resistant metal-coated multilayer steel pipe of the present invention.

FIG. 3 is an explanatory view showing an example of a method of injecting a resin.

[Explanation of symbols]

1 Corrosion-resistant metal plate, 2 block material, 3 steel pipe, 4 intermediate resin layer, 5 coil, 6 joining device, 7 holding roll, 8 pinch roll 9 welding machine, 10 filler, 11 inlet,
12 injection pump, 13 resin tank

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Morihiro Wada 2-11-9, Iwamotocho, Chiyoda-ku, Tokyo Japan Inside the Steel Corrosion Protection Co., Ltd. (72) Inventor Hideo Sakurai 2-11-9, Iwamotocho, Chiyoda-ku, Tokyo No. Japan Inside Steel Corrosion Protection Co., Ltd. (72) Inventor Toyo Ando 1 Kimitsu, Kimitsu City, Chiba Prefecture Inside the Kimitsu Plant Co., Ltd. (72) Inventor Masahiro Endo 1 Kimitsu City, Kimitsu City, Chiba Prefecture Nippon Steel Corrosion Protection Co., Ltd. Kimitsu factory

Claims (3)

[Claims] When manufacturing a multi-layer coated steel pipe having an intermediate resin layer and a corrosion-resistant metal coating on the outer circumference of a steel pipe, a block material for maintaining a gap is joined to a plurality of locations on one surface of a strip-shaped corrosion-resistant metal plate, The block material is brought into contact with the steel pipe surface and the corrosion-resistant metal plate is spirally wound around the steel pipe,
A method for producing a corrosion-resistant metal-coated multi-layer steel pipe, characterized by injecting a curable resin or a thermoplastic resin into a gap between the corrosion-resistant metal plate and the surface of the steel pipe. 2. The corrosion-resistant metal plate is made of titanium or an alloy thereof, and titanium or titanium clad steel is used as the block material, and the titanium surface is welded to the surface of the corrosion-resistant metal plate. A method for producing the corrosion-resistant metal-coated multilayer steel pipe according to the above. 3. The method for manufacturing a corrosion-resistant metal-coated multi-layer steel pipe according to claim 1, wherein the block material is made of a hardening resin or a thermoplastic resin, and the block material is joined to the surface of the corrosion-resistant metal plate. .