JPH1058030A - Manufacturing method of multi-layer coated steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which an intermediate resin layer and a surface coating layer of a corrosion-resistant metal plate are efficiently and inexpensively formed on the surface of a steel pipe, and a multi-layer coated steel pipe can be manufactured continuously in a simple process. I do. SOLUTION: After a curable resin or a thermoplastic resin is impregnated into a belt-like sheet of inorganic or organic fiber, the belt-like sheet is overlapped with a belt-like corrosion-resistant metal plate, and the corrosion-resistant metal plate is placed outside on the outer periphery of the steel pipe. By spirally winding in a co-winding manner, an intermediate resin layer is formed between the steel pipe and the corrosion-resistant metal coating.

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 Heretofore, for example, a corrosion-resistant steel pipe or a corrosion-resistant steel pipe pile used in the ocean is coated or coated with polyethylene or urethane-based heavy corrosion protection. However, the corrosion resistance of these steel pipes is limited, and the life is 15 to
About 20 years, about 40 years in 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 Laid-Open Publication No. Hei 7-100527 discloses that a steel pipe is coated directly or in advance with an adhesive resin on the surface thereof, and then a corrosion-resistant metal plate is spirally wound around the outer periphery of the steel tube so that the edges of the metal plate are joined together. Are disclosed.

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 manufacturing a multi-layer coated steel pipe 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.

[0007]

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 inexpensively, and to continuously form a multilayer by a simple process. It is an object to provide a method capable of manufacturing a coated steel pipe.

Another object of the present invention is to provide a method for producing a durable multi-layer coated steel pipe with improved adhesion between the intermediate resin layer and the corrosion-resistant metal coating layer.

[0009]

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 steel pipe having an intermediate resin layer and a corrosion-resistant metal coating on the outer periphery thereof. When manufacturing a layer-coated steel pipe, after impregnating a curable resin or a thermoplastic resin into a strip-shaped sheet of inorganic or organic fiber, the strip-shaped sheet is overlapped with a strip-shaped corrosion-resistant metal plate, and the steel pipe is set with the corrosion-resistant metal plate on the outside. And forming an intermediate resin layer between the steel pipe and the corrosion-resistant metal coating by spirally winding the outer circumference of the steel pipe in a co-winding manner.

(2) The edges of the corrosion-resistant metal plate wound in a spiral shape are overlapped with each other, and the edges are joined by seam welding, TIG welding, plasma welding or laser welding. A method for producing a multi-layer coated steel pipe according to the above (1).

(3) The multilayer coating according to the above (1), wherein the edge of the corrosion-resistant metal plate is bent to join the adjacent edges in a bent shape. This is a method for manufacturing a steel pipe.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of a method for manufacturing a multilayer coated steel pipe according to an embodiment of the present invention. The steel pipe 1 is placed on the trolley 2 and rotated in the direction of arrow A by the turning roll 3 on the trolley. The trolley 2 is run on the rail 4 and the steel pipe is moved at a predetermined speed in the direction of arrow B.

The belt-like sheet 5 made of inorganic or organic fibers is fed out of the coil, and is run in a resin impregnation tank 6 in which a fluid resin is stored, and the resin in the tank is impregnated into the belt-like sheet 5. By adjusting the gap between the pinch rolls 7 at the outlet of the impregnation tank 6, excess resin is squeezed out so that the resin-impregnated band-shaped sheet 5 has a predetermined thickness.

On the other hand, the strip-shaped corrosion-resistant metal plate 8 is fed out of the coil by a pinch roll 9 at a predetermined speed. A belt-shaped sheet 5 impregnated with the above-described resin is superposed on the lower side of the corrosion-resistant metal plate. After the two are brought into close contact with a pinch roll 10, they are integrally wound around the surface of the rotating and moving steel pipe 1 in a spiral manner. A pressure roll 11 is provided at the winding part, and the resin layer is
Press so that it adheres tightly.

As described above, according to the method of the present invention, the surface coating of the intermediate resin layer and the corrosion-resistant metal plate can be continuously formed in one step.

FIG. 1 shows a state in which the belt-like sheet 5 and the corrosion-resistant metal plate 8 are overlapped without any displacement in the width direction, but as shown in FIG. It can be shifted by a predetermined width to the rear side in the direction and can be overlapped with the corrosion-resistant metal plate 8. If they are staggered like this,
The position of the edge of the corrosion-resistant metal plate 8 and the edge of the band-shaped sheet 5 do not coincide with each other, which is effective in improving the sealing performance of the edge.

The corrosion-resistant metal plate 8 used in the present invention is a thin plate made of titanium, a titanium alloy, stainless steel or the like. Titanium or an alloy thereof is preferable from the viewpoint of corrosion resistance against seawater, and the plate thickness is 0.2. It is about 1.6 mm.

The strip-shaped sheet 5 impregnated with resin is
It is only necessary to have a certain level of strength and resin holding power, and woven or non-woven fabrics of inorganic or organic fibers can be used.
For example, glass cloth or woven fabric of vinylon fiber is suitable.

The resin used in the present invention is a resin impregnation tank 6
Any material may be used as long as it has a certain degree of fluidity in the inside, and after being wound around a steel pipe, adhesively hardens. A wide range of curable resins or thermoplastic resins can be used, for example, polyethylene, vinyl chloride, urethane, epoxy,
Polyester-based resins are suitable.

In the present invention, in order to prevent seawater from entering from a seam of the corrosion-resistant metal plate wound in a spiral shape, the edges of the metal plates may be overlapped with each other or joined by butt-joining the ends. desirable. As a joining method, a method of fusion welding from the viewpoint of sealing properties and durability, or a method of folding the edge portion and joining them in a folded shape is suitable.

In the welding method, since the thickness of the durable metal plate is as thin as 1.6 mm or less and it is necessary to avoid the influence of heat on the intermediate resin layer, applicable methods are restricted. As a result of various studies, it is appropriate to use any of seam welding, TIG welding, plasma welding, and laser welding.

FIG. 3 is an explanatory view showing an example of a method of welding the edges of the corrosion-resistant metal plate. FIG. 3 (a) shows a case where the edges of the corrosion-resistant metal plate 8 are overlapped with each other and resistance welded by the seam welding machine 12. FIG. 3B shows a method of applying heat energy from the welding torch 13 to perform fusion welding. In the case of FIG. 3 (b), the diameter of the thermal energy beam from the welding torch 13 can be reduced, and TIG welding with good control of the input energy can be achieved.
It is necessary to use either plasma welding or laser welding.

According to these welding methods, it is possible to minimize welding defects due to the corrosion-resistant metal plate 8 erosion and thermal influence on the lower intermediate resin layer 14. Further, in the step of winding the corrosion-resistant metal plate 8 and the belt-shaped sheet 5 around the steel pipe 1, the edges of the metal plates can be simultaneously and continuously joined, and the manufacturing process can be simplified.

FIG. 4 is an explanatory view showing an example of a method of joining the edges of the corrosion-resistant metal plate in a bent shape. As shown in FIG. 4 (a), a corrosion-resistant metal plate 8 having the same width or a wide width as the strip-shaped sheet 5 impregnated with resin is used. Orientation bending, and outward bending on the front edge.

When winding the bent corrosion-resistant metal plate 8 around the steel pipe 1 in a spiral manner, FIG.
As shown in FIG. 4 (b), the both bent portions are overlapped, pressed against the surface of the steel pipe by a roll or other pressing means, and joined in a bent shape as shown in FIG. 4 (b).

FIG. 5 is an explanatory view showing another example of the seam-fold joining, in which the positions of the edge portions of the strip-shaped sheet 5 and the corrosion-resistant metal plate 8 are shifted. In this case, as shown in FIG. 5A, the resin impregnated in the band-shaped sheet 5 is press-fitted into the gap between the folded portions. The resin impregnated in the band-shaped sheet exudes, instead of the band-shaped sheet entering the gap portion of the sea-fold, and seals the sea-fold.

Thus, when the folded portion is bent, a resin film 15 is formed as shown in FIG. 4 (b), which serves as a seal material to completely prevent seawater from entering. .

[0028] In such a seam-fold joining method, when the corrosion-resistant metal plate 8 and the strip-shaped sheet 5 are wound around the steel pipe 1, the edges of the metal plates can be simultaneously joined together continuously, and the intermediate layer between the lower layers can be formed. It is possible to obtain a durable joint structure that does not affect the resin layer by heat.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-layer coated steel pipe was manufactured by the method shown in FIG.
And a pure titanium plate was used as the corrosion-resistant metal plate 8. 400mm wide glass cloth strip
Then, the belt-like sheet 5 was impregnated with a urethane resin in a resin impregnation tank, and then superposed on a titanium plate having a width of 400 mm and a thickness of 0.4 mm, and wound spirally around the outer periphery of the steel tube sheet. The winding speed was about 5 m / min in peripheral speed.

The edges of the titanium plates were overlapped by about 30 mm, and these were joined by seam welding as shown in FIG. Since the glass cloth and the titanium plate wound in a spiral form generate excess winding allowance at both ends of the steel pipe pile, they were cut and shaped according to the shape of both ends of the steel pipe.

By manufacturing a steel pipe to be coated by such a method, it is possible to continuously form the intermediate resin layer and the metal coating and join the edges of the metal coating in one step. . The working time for coating one 7 m long steel pipe is about 25 minutes, and the production speed is higher than the conventional method of forming the intermediate resin layer and the surface coating separately, so that the working cost is greatly reduced. Was.

Further, the coated steel pipe to be coated manufactured by the method of the present embodiment has a uniform thickness of the intermediate resin layer and good adhesion, and can withstand long-term use as an offshore structure. I was assured.

[0033]

According to the present invention, the intermediate resin layer and the metal coating can be continuously formed in one step. In addition, since the strip-shaped resin-impregnated sheet and the metal plate are spirally wound, the work can be performed regardless of the change in the curved surface due to the difference in the diameter of the steel pipe, and the work can be simplified and automated. Furthermore, it became possible to form an intermediate resin layer as an impact buffer layer with a uniform thickness and good adhesiveness, thereby improving the reliability of the product.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for manufacturing a multilayer coated steel pipe according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of how a corrosion-resistant metal plate and a belt-like sheet are stacked.

FIG. 3 is an explanatory view showing an example of a method for welding edges of a corrosion-resistant metal plate.

FIG. 4 is an explanatory view showing an example of a method of joining edges of a corrosion-resistant metal plate in a bent shape.

FIG. 5 is an explanatory view showing another example of a method of joining in a folded shape.

[Explanation of symbols]

1 steel pipe, 2 bogies, 3 turning rolls,
4 rail, 5 belt-shaped sheet, 6 resin impregnated layer, 7 pinch roll, 8 corrosion-resistant metal plate,
9, 10 pinch roll, 11 pressure roll, 12
Seam welding machine, 13 welding torch, 14 intermediate resin layer, 15 resin coating

 ──────────────────────────────────────────────────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 producing a multi-layer coated steel pipe having an intermediate resin layer and a corrosion-resistant metal coating on the outer periphery of the steel pipe, a band-shaped sheet of inorganic or organic fibers is impregnated with a curable resin or a thermoplastic resin. It is possible to form an intermediate resin layer between the steel pipe and the corrosion-resistant metal coating by overlapping the belt-like sheet with the corrosion-resistant metal sheet in the form of a strip and winding the steel sheet around the outer circumference of the steel pipe with the corrosion-resistant metal sheet facing outward. A method for producing a multi-layer coated steel pipe. 2. An edge of the corrosion-resistant metal plate wound in a spiral shape is overlapped with each other, and seam welding is performed.
The method according to claim 1, wherein the edges are joined by welding, plasma welding, or laser welding. 3. The method for manufacturing a multi-layer coated steel pipe according to claim 1, wherein the edge of the corrosion-resistant metal plate is bent to join the adjacent edges in a bent shape. .