JPH1058150A - Method for coating corrosion resistant metallic sheet on steel tube or steel tube pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method for a corrosion resistant metallic sheet capable of performing sure and efficient welding by spirally coiling the corrosion resistant metallic sheet so that an overlapped part is located on an upper surface of a steel strip to protect the coating by the steel strip from the heat. SOLUTION: A steel strip 8 is heated to e.g. 100-300 deg.C by a heating equipment, and brought into contact with a coating 1c, an area of the coating 1c with which the steel strip 8 is brought into contact is softened, and the steel strip 8 is coiled while it is embedded in the coating 1c. The coiling position is adjusted so that an overlapped part dd of a corrosion resistant metallic sheet 3s is located on an upper surface of the steel strip 8. Indirect resistance welding is performed on the overlapped part dd of a side end part of the corrosion resistant metallic sheet 3s with the steel strip 8 as a backing. An indirect resistance welding machine 7 is slidably arranged in the axial direction of a coated steel tube pile 1, and slides slightly along the side end surface of the corrosion resistant metallic sheet 3s coiled around the coated steel tube 1 through a copying mechanism even when the turning and feed speed of the coated steel tube 1 by a turning and feed device 2 is fluctuated, and welding can be performed with excellent accuracy for the prescribed weld seam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of, for example, winding a corrosion-resistant metal sheet in a spiral shape around a coated steel pipe (pile) used for marine structures and requiring high corrosion resistance.
By applying a backing metal at the formed overlap portion and performing indirect resistance welding, it is possible to apply a corrosion-resistant metal sheet to a coated steel pipe or a coated steel pipe pile, which is applied when coating a corrosion-resistant metal sheet on a coated steel pipe (pile). The present invention relates to a coating method.

[0002]

2. Description of the Related Art Conventionally, for example, in an offshore structure, a pile is often driven into the sea to form a foundation. Generally, steel pipe piles are used as the piles from the viewpoint of securing the strength.However, the steel pipe piles are highly corrosive, particularly in seawater splash zones, and have poor durability. The portion in contact with the splash zone has been used after being subjected to resin coating or heavy corrosion protection of polyethylene or urethane. However, these steel pipe piles, which have been subjected to heavy corrosion protection, have a limit in maintaining high corrosion resistance over a long period of time.
It is said to be 20 years and 40 years in the case of heavy corrosion protection.

On the other hand, in order to improve the corrosion resistance of the pile, it has been proposed to form the pile body with a corrosion-resistant material such as stainless steel or stainless steel and clad steel made of ordinary steel.
The pile made of the clad steel is not practically used because of its high initial cost and high cost. In order to solve such disadvantages, Japanese Patent Application Laid-Open No. 2-256713 proposes a steel pipe pile subjected to anticorrosion treatment. This steel pipe pile is coated with an ordinary coating base on the outer surface, coated with an adhesive resin having corrosion resistance and elasticity, and wound around a corrosion-resistant metal thin plate with embossed irregularities, while tightening it. It is an anticorrosion steel pipe pile that has been folded or caulked. This steel pipe pile requires coating ground treatment and resin coating treatment, and furthermore, coats and fastens a corrosion-resistant metal sheet with embossed irregularities having a width and length corresponding to the pipe diameter and coating length of the steel pipe pile. And it is difficult to secure high productivity. In addition, a remarkable seam portion is formed in the circumferential direction of the steel pipe of the corrosion-resistant metal sheet to be coated, and it becomes difficult to coat with excellent shape.

On the other hand, Japanese Utility Model Laid-Open Publication No. Sho 62-44948 proposes a steel pipe pile which has been subjected to anticorrosion treatment using a titanium sheet having excellent corrosion resistance as a metal sheet to be coated. As shown in FIG. 6A, the steel pipe pile sp is attached with an L-shaped steel s made of corrosion-resistant metal to the outer peripheral surface of the steel pipe pile sp coated with the resin jc by welding w, as shown in FIG. 8B. Then, both ends of the corrosion-resistant metal plate ts are fastened to the L-shaped steel s with bolts and nuts bn made of corrosion-resistant metal, and the steel pipe pile s
It has a configuration in which the p surface is covered with a corrosion-resistant metal plate ts to prevent corrosion. However, when this steel pipe pile is formed, it is necessary to weld and attach the corrosion-resistant metal L-shaped steel s to the steel pipe pile, so that the manufacturing cost is high. When the L-shaped steel is brought into contact with the steel sheet, there is a concern that the organic solvent of the film is exuded by the welding heat and the weldability is impaired. The corrosion-resistant metal plate ts is attached to the steel pipe pile sp by bolts and nuts bn with L-shaped steel s interposed.
When this steel pipe pile is driven into the sea, it is necessary to mount the corrosion-resistant metal plate ts by underwater work by a diver, and the workability is poor and the mounting cost is increased. There is.
Further, when, for example, a resin paint is applied to the outer peripheral surface of the steel pipe pile, when the corrosion-resistant metal plate is spirally wound and the edges thereof are welded to each other, the organic solvent of the coating film is formed by welding heat. However, there is a concern that the weldability may be impaired due to boiling.

[0005]

SUMMARY OF THE INVENTION The present invention is based on the premise that a steel pipe pile which is used as a base of an offshore structure and requires high corrosion resistance is coated with a corrosion-resistant metal plate. In this case, even if the steel pipe pile has a coating, welding can be performed reliably and efficiently without any problems such as the organic solvent of the coating being exuded by the welding heat and impairing the weldability. The present invention provides a method for coating a corrosion-resistant metal sheet.

[0006]

According to the present invention, a tip of a corrosion-resistant metal sheet is fixed to an outer peripheral surface of a coated steel pipe (pile), and the corrosion-resistant metal sheet is fed in an axial direction while rotating the coated steel pipe (pile). When forming the overlapped portion at the side end thereof and spirally winding the coated steel pipe (pile) with the corrosion-resistant metal sheet by indirect resistance welding, before winding the corrosion-resistant metal sheet, stack the corrosion-resistant metal sheet. The coating area of the coated steel pipe (pile) where the part is located is heated to soften the coating area, and the steel strip to be the backing metal material is spirally wound while being pressurized and embedded in the softened coating. A method for coating a corrosion-resistant metal thin plate on a coated steel pipe or a coated steel pipe (pile), wherein the coated steel pipe or coated steel pipe (pile) is wound in a spiral shape so that an overlapped portion is located on an upper surface.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a corrosion-resistant thin metal sheet is spirally wound around a coated steel pipe (pile) while forming an overlapped portion at its side end, and a backing metal is arranged at the overlapped portion. When indirect resistance welding is performed to coat a corrosion-resistant metal sheet on a coated steel pipe (pile), before winding the corrosion-resistant metal sheet, a steel strip to be a backing metal material is spirally wound, and the top of this steel strip is wound. By winding the corrosion-resistant metal sheet in a spiral shape so that the overlapped part is located, the steel strip protects the coating from the welding heat, prevents the organic solvent in the coating from boiling, and ensures reliable and efficient welding. It is possible.

When this steel strip is spirally wound around a coated steel pipe (pile), the coating area of the coated steel pipe (pile) where the steel strip is located is heated to appropriately soften the coating area, and this softening is performed. By pressing the steel strip uniformly into the area, it is evenly contacted with the lower surface of the corrosion-resistant metal sheet, ensuring the backing metal function and stabilizing the backing metal step to minimize the gap generated at the step. By reducing the size, it is possible to reduce the burden of filling work such as resin for shielding the gap.

The heating temperature for heating the coating region of the coated steel pipe (pile) depends on the diameter of the coated steel pipe (pile), the type and thickness of the coating, the thickness and width of the steel strip, etc.
What is necessary is just 0-300 degreeC. If the temperature is lower than 100 ° C., the softening is insufficient and it is difficult to embed the steel strip, and the adhesiveness to the steel strip cannot be sufficiently secured. On the other hand, at a temperature of 300 ° C. or higher, the coating melts and drips, losing the function of the coating.

The winding of the steel strip around the coated steel pipe (pile) may be performed as a separate step before winding the corrosion-resistant metal sheet around the coated steel pipe (pile), but the corrosion-resistant metal sheet is wound around the coated steel pipe (pile). It may be performed simultaneously when winding. However, in this case, in order to prevent displacement of the steel strip, it is preferable to wind the corrosion-resistant metal sheet after allowing time for the coating to solidify and the steel strip to be firmly fixed in the coating.

As a means for heating the film, a method of directly heating the film by a heating method using a flame or hot air as a heat source (direct spraying or indirect heating with a radiation tube interposed) can be said to be general. A method or other electric heating method may be used, and the coating may be heated through the steel strip by directly or indirectly heating the steel strip and then winding the coated steel pipe (pile). . In this case, it is easy to heat the coating in the minimum necessary range.

As a means for pressing the steel strip, a pressing roller equipped with a pressing device is preferable. The pressing force (load) is a case of a polyethylene resin film, and the heating temperature is 100 to 30.
When the temperature is 0 ° C., the outer surface of the steel strip having a thickness of 3.0 to 9.0 mm is easily buried at 10 to 50 kg / mm ² until it matches the outer surface level of the coating of the non-buried portion. Can be. This pressing force depends on the softened state of the coating,
The outer surface of the steel strip is adjusted so that it can be easily matched with the outer surface level of the coating of the non-embedded portion.

As a means for welding the overlapped portion at the side end portion of the corrosion-resistant metal sheet, an indirect resistance welding method that can easily perform welding from the outer peripheral surface side without adversely affecting the coating film is optimal. As a means for fixing the winding start end and the winding end of the steel strip and the corrosion-resistant metal thin plate, various welding methods, an adhesive method, a mechanical fixing method, and the like can be used.

As a welding method, an indirect resistance welding method is preferable. According to this indirect resistance welding method, a joining portion can be stably obtained by a strong pressing force, and a joining speed is high and joining can be performed at low cost. In addition, a healthy joint can be obtained without leakage of the resin.

Hereinafter, the present invention will be described with reference to FIGS. 1 to 5 together with an example of arrangement of coating equipment for implementing the present invention. This example covers a coated steel pipe pile. 1 and 2, reference numeral 1 denotes a coated steel pipe pile formed by coating a coating 1c on a steel pipe 1p.
The paper can be fed in the direction of the arrow while rotating by the rotation / feed device 2 including three rotating rollers 2a, 2b, and 2c. Reference numeral 3 denotes a corrosion-resistant metal coil.
3s is rewound by the pinch roller 4 and supplied to the coated steel pipe pile 1 side via the support roller 5, and the tip is fixed to the outer peripheral surface of the coated steel pipe pile 1.

The tip of the corrosion-resistant metal sheet 3 is spirally wound by driving the rotating / feeding device 2 while forming an overlapping portion dd at a side end on the outer peripheral surface of the coated steel pipe pile 1. The overlapped portion dd is subjected to indirect resistance welding by an indirect resistance welding machine 7 supported on a gantry 6 to fix and coat the corrosion-resistant metal sheet 3s on the coated steel pipe pile 1.

A steel strip 8 serving as a backing metal is spirally wound between the overlap portion dd of the corrosion-resistant metal sheet 3s and the outer peripheral surface of the coated steel pipe 1 before winding the corrosion-resistant metal sheet 3s. Direct resistance welding is performed in a state where a backing metal made of the steel strip 8 is arranged. When the steel strip 8 serving as the backing metal is wound around the coated steel pipe prior to the winding of the corrosion-resistant metal sheet 3s, the steel strip 8 was unwound from the steel strip coil 8s by the pinch roller 9 as shown in FIGS. The steel strip 8 is supplied to the outer peripheral surface of the coated steel pipe pile 1 via the support roller 10 and the tip thereof is fixed, and the coated steel pipe pile 1 is rotated by driving the rotation / feeding device 2 to feed the steel pipe in the direction of the arrow. Steel pipe pile 1 covering belt 8
Spirally wound around the outer peripheral surface of.

Prior to the winding, in the vicinity of the coating 1c region of the coated steel pipe pile 1 around which the steel strip 8 is to be wound, the steel strip 8 is heated to 100 to 300 ° C. by the heating device 11 and then brought into contact with the coating 1c. While softening the region of the coating 1c with which the steel strip 8 contacts,
The steel strip 8 is wound while being buried in the coating 1c by applying pressure with a pressure roller 14 supported via 3.

In this case, the front end and the rear end of the steel strip 8 are adhered and fixed to the coating 1c of the coated steel pipe pile 1. However, if the steel strip 8 is further firmly fixed together with welding, the corrosion-resistant thin metal sheet 3s is wound. In this case, the winding is started after welding the tip to the steel strip 8, and after the winding is completed, the winding end is set to the steel strip 8.
Can be fixed by welding.

When winding the corrosion-resistant metal sheet 3s,
The winding position is adjusted so that the overlap portion dd of the corrosion-resistant thin metal plate 3s is positioned on the upper surface of the steel strip 8. The adjustment of the winding position may be performed manually by visual judgment, or the rotation / feed speed of the coated steel pipe pile 1 and the corrosion-resistant metal sheet 3 may be adjusted.
It may be adjusted by automatically controlling the supply speed of s.

The overlapping portion dd at the side end of the corrosion-resistant thin metal plate 3s
The indirect resistance welding machine 7 for performing indirect resistance welding using the steel strip 8 as a backing metal is conceptually configured as shown in FIG. That is, the pressurizing device 15
a, a welding-side roller electrode 16 provided with a
And a non-welding side (earth side) wide roller electrode 17 provided with a non-welding side (earth side). The welding side roller electrode 16 is pressed and abutted on the upper surface of the overlapping portion dd of the corrosion-resistant thin metal plate 3s, and The side) wide roller electrode 17 is pressed and abutted on the non-overlapping portion of the corrosion-resistant thin metal plate 3 s which is at a distance x away from the welding-side roller electrode 16.

The two roller electrodes 16, 17 are connected via a power supply 18, and
A power supply circuit between the power supply 17 and the power supply 18 includes an electric resistance measuring device 19.
a, 19b are provided, and the electric resistance at each electrode is measured during welding, and the power supply 18 is controlled via the arithmetic and control unit 20 so that the electric resistance at each electrode is maintained in a predetermined region. be able to. The pressing devices 15a, 15b of the respective roller electrodes are respectively provided with pressure measuring devices 21a, 21a.
1b is provided, and the pressing force at each electrode is measured during welding, and the pressing device 15 is operated via the arithmetic and control unit 20 so that the pressing force at each electrode is maintained in a predetermined region.
a, the pressurizing force by 15b can be controlled.

The indirect resistance welding machine 7 is disposed on the gantry 5 so as to be slidable in the axial direction of the coated steel pipe pile 1, and the rotation / feed speed of the coated steel pipe pile 1 by the rotation / feed device 2 varies. However, the corrosion-resistant metal sheet 3s wound around the coated steel pipe pile 1 by a copying mechanism (not shown)
And can be welded with high precision to a predetermined welding line by sliding along the side end surface of the slab.

When the corrosion-resistant metal sheet 3s is coated on the coated steel pipe pile 1 by indirect resistance welding, the corrosion-resistant metal sheet 3s is rewound from the corrosion-resistant metal coil 3 and its tip is mechanically attached to the tip of the coated steel pipe pile 1. The coated steel pipe pile 1 is temporarily fixed, and is fed in the direction of the arrow while rotating the coated steel pipe pile 1 with the rotation / feed device 2 in a state where the side ends are overlapped.
The welding-side roller electrode of the indirect resistance welding machine 7 abutted and arranged on the upper surface of the overlapped portion dd while forming the overlapped portion dd on the steel strip 8 serving as the backing metal embedded in the coating 1c. 16 and the non-welding side (earth side) wide roller electrode 17 disposed in contact with the non-welding portion side, indirect resistance welding is performed by applying a current, and a corrosion-resistant metal thin plate 3 s is spirally formed on the outer peripheral surface of the coated steel pipe pile 1. Can be wound and coated. Corrosion resistant metal sheet 3s coated steel pipe pile 1
In the case where a gap is formed between the outer peripheral surfaces, it is desirable to press-fit a filler into the gap to increase the water stopping property.

By carrying out the present invention configured as described above, a steel strip which becomes a backing metal when a corrosion-resistant metal sheet is spirally wound around a coated steel pipe (pile) and coated by indirect resistance welding. Protects the coating from welding heat and prevents the organic solvent in the coating from evaporating, enabling reliable and efficient welding, and coating the coated steel pipe (pile) with a corrosion-resistant metal sheet without damaging the coating Can be formed firmly.

The steel strip serving as the backing metal is pressed and uniformly embedded in the coating of the coated steel pipe (pile) so as to uniformly contact the lower surface of the corrosion-resistant metal sheet, thereby stably ensuring the function of the backing metal. By minimizing the step due to the backing metal and minimizing the gap generated in the step, the burden of the work of filling resin or the like for shielding the gap can be reduced.

It should be noted that the present invention is not limited only to the case of using the above-mentioned coating equipment, but is applicable to the coating equipment for implementing the present invention. The position of the arrangement, the pressurizing mechanism, the heating device, the heating method, various measurement and control mechanisms, their arrangement, and the like are changed within the range in which the present invention can be implemented according to the welding target, welding conditions, and the like. It is. As the corrosion-resistant metal thin plate, titanium, titanium alloy stainless steel, aluminum, hot-dip galvanized steel sheet, aluminum-plated steel sheet, or the like can be used.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to spirally winding a titanium sheet as a corrosion-resistant metal sheet on a coated steel pipe pile having a urethane-based resin coating by selectively using a coating equipment example as shown in FIGS. The coating area of the coated steel pipe pile where the overlap formed at the side end of the sheet metal is located is heated to soften the coating, and the steel strip to be the backing metal is pressed and embedded in this softened coating while spiraling. An experiment was conducted in which the titanium sheet was spirally wound and covered so that the overlapped portion was positioned on the steel strip. Experimental conditions and evaluation results will be described below. Experimental conditions ・ Coated steel pipe Steel pipe: JIS A 5525 Material: General structural steel (SKK 400) Thickness: 12 mm Coating material: Urethane resin Thickness: 5 mm Rotation speed: 3600 mm / min Feeding speed: 120 mm / min Titanium thin plate Material: Class 1 TP270C of JIS H4600 Width: 1200mm Thickness: 0.7mm ・ Steel band (backing metal) Material: SPHC plate Width: 100mm Thickness: 4.0mm ・ Indirect welding Welding current: 12000A Pressing force: 90-480kg / mm ² Roller electrode Welding side diameter: 150mm Contact width: 3mm Pressing force: 100-300kg / mm ² Non-welding side (earth side) Diameter: 150mm Contact width: 16mm Pressing force: 500kg / mm ² Constant welding speed: 2500mm / min ・ Heating device: Flame burner Heating temperature: 100-300 ° C ・ Pressing device: Pressing roll Pressure: 10-50kg / mm ²

The welding strength of the titanium thin plate of the coated steel pipe pile obtained in this experiment, the influence on the steel pipe pile coating (resin coating), and the like were examined. As a result, in the experimental example of the present invention, the welding strength was sufficient, there was no deterioration or destruction of the steel pipe pile coating at the welded portion, and no insulation failure due to the boiling of the organic solvent in the steel pipe pile coating was observed. .

Further, the gap between the steel strip to be the backing metal wound around the coated steel pipe pile and the overlapped portion of the titanium thin plate can be reduced, and the work of filling the filler into the gap can be minimized. did it.

At the time of welding, since a strong pressure is applied, the steel strip is fixed between the resins, and direct welding of iron-titanium-titanium is performed. However, since the bottom is a hard steel strip, The pressure became constant and stable joining was achieved.

[0032]

According to the present invention, prior to winding a corrosion-resistant metal sheet around a coated steel pipe (pile), a steel strip serving as a backing metal material is spirally wound so that an overlapped portion is positioned on the upper surface of the steel strip. By spirally winding a corrosion-resistant metal sheet in a spiral shape, it is possible to protect the coating from welding heat with a steel strip, prevent the organic solvent in the coating from boiling, and perform welding reliably and efficiently.

When a steel strip is spirally wound around a coated steel pipe (pile), the coating region where the steel strip is located is heated and softened, and the steel strip is uniformly pressed into the softened area. A resin for shielding the gap by uniformly contacting the lower surface of the corrosion-resistant metal sheet, ensuring the function of the backing metal, and minimizing the step formed by the backing metal to minimize the gap generated at the step. The burden of the filling work can be reduced.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a partially cutaway plan conceptual explanatory view showing an example of a facility for coating a corrosion-resistant metal sheet on a coated steel pipe pile and a winding state of the corrosion-resistant metal sheet on a coated steel pipe pile according to the present invention.

FIG. 2 is a partial conceptual explanatory view taken along the line Aa-Ab in FIG. 1;

FIG. 3 is a partially sectional plan conceptual explanatory view showing an example of a facility for coating a steel strip (backing metal) on a coated steel pipe pile and a winding state of the steel strip on the coated steel pipe pile according to the present invention.

FIG. 4 is a conceptual explanatory view of a section taken along line Ba-Bb in FIG. 3;

FIG. 5 is a conceptual front view showing an example of an indirect resistance welding machine used in the present invention.

FIG. 6 is a three-dimensional conceptual explanatory view showing an example of coating a corrosion-resistant metal plate on a steel pipe in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coated steel pipe pile 1p Steel pipe 1c Coating 2 Rotating / feeding device 2a, 2b-2c Rotating roller 3 Corrosion-resistant metal coil 3s Corrosion-resistant metal thin plate 4 Pinch roller 5 Support roller 6 Mount 7 Indirect resistance welder dd Lap part 8 Steel strip (back) 8s steel strip coil 9 pinch roller 10 support roller 11 heating device 12 gantry 13 pressure device 14 pressure roller 15a, 15b pressure device 16 welding-side roller electrode 17 non-welding-side roller electrode 18 power supply 19a, 19b electric resistance Measuring device 20 Arithmetic control device 21a, 21b Force measuring device Sp Steel pipe pile Jc Resin ts Titanium thin plate s Shape steel bn Bolt / nut

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazumi Matsuoka 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Koji Homma 20-1 Shintomi, Futtsu-shi, Chiba New Japan (72) Kazuhiro Kinoshita, 2-6-3 Otemachi, Chiyoda-ku, Tokyo Nippon Steel Corporation (72) Yasuo Takahashi, 2-6-3, Otemachi, Chiyoda-ku, Tokyo Nippon Steel Corporation

Claims (1)

[Claims] 1. A tip of a corrosion-resistant metal sheet is fixed to an outer peripheral surface of a coated steel pipe (pile), and the corrosion-resistant metal sheet is fed in an axial direction while rotating the coated steel pipe (pile). When forming a corrosion-resistant metal sheet on a coated steel pipe (pile) by spirally winding it and forming it by indirect resistance welding, the coated steel pipe (pile) where the overlapping portion of the corrosion-resistant metal sheet is located before winding the corrosion-resistant metal sheet ) Is heated to soften the coating area, and the steel strip serving as the backing metal material is spirally wound in the softened coating while being pressurized and embedded, so that the overlapped portion is positioned on the upper surface of the steel strip. A method for coating a corrosion-resistant metal sheet on a coated steel pipe or a coated steel pipe (pile), wherein a corrosion-resistant metal sheet is spirally wound around the metal pipe.