JP2007167933A - Coated steel tube manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated steel tube having the excellent corrosion-resistant capacity by reducing the amount of residual air in a space formed between the outer surface of the steel tube and the inner surface of a coating material. <P>SOLUTION: When at least a part of an outer surface of a steel tube 2 is covered with a plurality of coating materials 3-7 over the entire circumference, a plurality of belts 60 are wound around outer surfaces of the wound coating materials 3-7 in a circumferential direction and bound every time one of the coating materials 3-7 is wound around the outer surface of the steel tube 2 in a circumferential direction, the wound coating materials 3-7 are fastened and fixed to the outer surface of the steel tube 2, and after the coating materials 3-7 are tightly attached to the outer surface of the steel tube 2, the primary temporary welding is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a coated steel pipe in which the outer surface of a steel pipe of a marine steel structure is covered with a coating material such as a seawater-resistant metal over the entire circumference so as to prevent corrosion of the marine steel structure.

  In steel offshore structures (for example, piers, jackets, etc.), corrosive environments are particularly severe in tidal areas exposed to tidal periods. Corrosion-resistant metal coating technology that improves corrosion resistance by pasting and welding thin metal plates with excellent seawater resistance (such as titanium, stainless steel, etc.) to the entire tidal part of structural materials in recent years. Has been applied.

  As such a coating technique, Patent Document 1 discloses that a thin sheet metal as a coating material or a plurality of coating materials is wound around the outer surface of a steel pipe (element tube) in the circumferential direction and temporarily attached by welding. A covered steel pipe having a structure in which hermetic welding is performed on the entire peripheral portion of the material and the covering material and the steel pipe are joined is disclosed.

  In the coated steel pipe described in Patent Document 1, when the coating material is wound around the steel pipe and temporarily attached, if the thickness of the coating material is as thin as about 0.4 mm, it is wound around the steel pipe as it is and temporarily attached. If the plate thickness of the coating material is as thick as about 2.0 mm, for example, the coating material is previously formed into a shape suitable for the outer surface of the steel pipe by pressing or bending, and then wound around the steel pipe and temporarily attached. It is carried out.

JP 2004-131843 A

  However, in the coated steel pipe described in Patent Document 1, when the covering material is temporarily attached to the outer surface of the steel pipe, the covering material may be temporarily attached in a state where the covering material is not sufficiently adhered to the outer surface of the steel pipe. When temporary covering and sealing welding after temporary mounting are performed in a state where the cladding is not sufficiently adhered to the outer surface of the steel pipe, the resulting coated steel pipe has a large volume between the outer surface of the steel pipe and the inner surface of the cladding. Is likely to be formed. If there is such a space, folds and wrinkles are likely to enter the coating material when the coated steel pipe is moved or transported, and after construction, the coating material is scratched or cracked by a direct collision such as driftwood. The coating material is likely to be damaged, and the coating material is likely to be damaged, and the anticorrosion function may not be maintained.

  In addition, if tacking and sealing welding after tacking are performed in a state where the cladding is not sufficiently in contact with the outer surface of the steel pipe, an irregular shape is formed on the coated outer surface of the finished coated steel pipe, and the aesthetic appearance is impaired. End up.

  This invention is made | formed in view of the said subject, and it aims at providing the manufacturing method of the coated steel pipe which was excellent in anti-corrosion ability than before.

  In order to solve the above problems, according to the present invention, there is provided a method of manufacturing a coated steel pipe in which at least a part of an outer surface of a steel pipe is covered with a plurality of coating materials over the entire circumference, One of them is arranged at a predetermined position on the outer surface of the steel pipe, and a plurality of band-like fastening members are wound around the outer surface of the covering material arranged at the predetermined position in the circumferential direction and bound together. A bundling step of fixing the covering material arranged at the predetermined position to the outer surface of the steel pipe, a first welding step of welding the covering material fixed to the outer surface of the steel pipe to the outer surface of the steel pipe, and the predetermined position A binding release step of releasing the binding of the plurality of belt-shaped fastening members wound around the outer surface of the disposed covering material, and until the outer surface of the steel pipe is covered with the plurality of covering materials over the entire circumference, The placement step, the bundling step, the first welding step And a second welding step of further welding the plurality of coating materials covering the entire outer surface of the steel pipe, and then repeating the binding release step, and manufacturing the coated steel pipe A method is provided.

  The method for manufacturing a coated steel pipe may include a sealing step of sealing and welding the plurality of further welded coating materials to the outer surface of the steel pipe.

  In the method of manufacturing the coated steel pipe, in the arranging step, the covering material is positioned at a predetermined position on the outer surface of the steel pipe by positioning it by contacting a magnet attracted and fixed to the outer surface of the steel pipe. It may be.

  In the method for manufacturing a coated steel pipe, the bundling step includes a temporary fixing step of placing a magnet on the outer surface of the coating material arranged at the predetermined position, and temporarily fixing the coating material to the outer surface of the steel pipe by the magnetic force of the magnet. You may make it have.

  In the method of manufacturing the coated steel pipe, in the bundling step, the plurality of belt-shaped fastening members arranged at predetermined intervals over the entire length in the tube axis direction of the coating material arranged at the predetermined position are arranged as follows. Bundling may be performed sequentially from the axial center to both ends.

  In the method of manufacturing the coated steel pipe, in the bundling step, the covering material disposed at the predetermined position is moved in the circumferential direction by tightening when the plurality of belt-shaped tightening members are bound, and the circumferential position is determined. Fine adjustment may be made.

  In the manufacturing method of the coated steel pipe, in the first welding step, when welding is performed along the pipe axis direction of the steel pipe, discontinuous welding is performed at a plurality of local welding locations, The position and order of welding may be determined so that the welding locations are uniformly distributed in the pipe axis direction within the range in which welding is performed along the pipe axis direction of the steel pipe.

  In the method for manufacturing the coated steel pipe, in the first welding process, when welding is performed along the circumferential direction of the steel pipe, discontinuous welding is performed at a plurality of local welding locations, and the plurality of welding steel pipes are welded. The positions and the welding order may be determined so that the locations are uniformly distributed in the circumferential direction in the range where the welding along the circumferential direction of the steel pipe is performed.

  In the method of manufacturing the coated steel pipe, the steel pipe may be rotated about a pipe axis to adjust the position of the outer surface of the steel pipe or the position of the covering material arranged at the predetermined position.

  In the method of manufacturing the coated steel pipe, in the binding release step, both end portions of the plurality of band-shaped fastening members that have been released from the binding may be held at predetermined positions.

  According to the present invention, when a plurality of coating materials are temporarily attached to the outer surface of a steel pipe, the plurality of coating materials are welded and temporarily attached in a state of being in close contact with the outer surface of the steel pipe. The volume of the space formed between the outer surface of the steel pipe and the inner surface of the covering material of the coated steel pipe can be reduced, the amount of residual air remaining in this space can be reduced, and the anticorrosion ability has been improved. Coated steel pipes can be manufactured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view of a coated steel pipe 1 manufactured by a manufacturing method according to an embodiment of the present invention described later. As shown in FIG. 1, in this embodiment, the coated steel pipe 1 includes five rectangular sheet-like coating materials 3 to 7 along the circumferential direction on the outer peripheral surface of a steel pipe 2 configured in a circular tube shape. The covering members 3 to 7 are arranged and hermetically welded to the outer peripheral surface of the steel pipe 2. Moreover, in this Embodiment, the stainless steel plate is used as the coating materials 3-7, for example. FIG. 2 is a side view of the coated steel pipe 1. 3 is a cross-sectional view taken along the line AA in FIG.

  As shown in FIGS. 2 and 3, the covering material 3 is arranged so that one end 3U in the circumferential direction overlaps with the end 4D in the circumferential direction of the covering 4 and the other end in the circumferential direction. The portion 3D is arranged so as to overlap under the circumferential end portion 7U of the covering material 7. Similarly, each of the end portions 4D to 7D in the circumferential direction of the respective covering materials 4 to 7 is disposed so as to overlap with the respective end portions 3U to 6U of the other covering materials 3 to 6, respectively. The other end portions 4U to 7U in the circumferential direction of the materials 4 to 7 are arranged so as to overlap with the respective end portions 5D to 7D and 3D of the other covering materials 5 to 7 and 3, respectively.

  FIG. 4 is an enlarged view of a portion where the end portion 3U of the covering material 3 and the end portion 4D of the covering material 4 overlap in FIG. As shown in FIG. 2, in this overlapping portion, the steel pipe 2 and the covering materials 3 and 4 are indirect seam welded along the pipe axis direction of the coated steel pipe 1 (that is, the pipe axis direction of the steel pipe 2). The end portion 3U of the covering material 3 made of steel and the end portion 4D of the covering material 4 are melt-bonded, and the end portion 4D of the covering material 4 made of stainless steel and the steel pipe 2 made of ordinary steel are fixed. A solid phase bonding portion 11 to be phase bonded is hermetically formed.

  In the above description, the portion where the end portion 3U of the covering material 3 and the end portion 4D of the covering material 4 overlap with each other has been described with reference to FIG. 4, but the end portions 3U to 7U and 3D to 7D of the covering materials 3 to 7 Similarly, other portions that overlap each other are also indirect seam welded along the pipe axis direction of the steel pipe 2, and the fusion bonded portion 10 between the covering materials 3 to 7 and the covering materials 3 to 7 and the steel pipe 2 are connected. The inherent joint 11 is hermetically formed.

  FIG. 5 is a perspective view showing one end of the coating material 3 and the coating material 4 in the tube axis direction of the steel pipe 2. As shown in FIG. 2, the covering material 3 and the covering material 4 are TIG welded along the circumferential direction of the steel pipe 2 at both ends in the tube axis direction, and TIG welds 12 and 13 hermetically bonded to the steel pipe 2 are sealed. Is formed. TIG welding is similarly performed on both ends of the covering materials 5 to 7 in the tube axis direction. In addition, since TIG welding of the coating | covering materials 5-7 is performed continuously, the TIG welding parts 12 and 13 have the cyclic | annular structure which goes around the steel pipe 2 in the circumferential direction.

  Each of the covering materials 3 to 7 is composed of the melt joint 10 and the solid phase joint 11 by indirect seam welding along the pipe axis direction of the steel pipe 2 and the TIG welds 12 and 13 along the circumferential direction of the steel pipe 2. Between the inner surface and the outer surface of the steel pipe 2, as shown in FIG. 2, sealed closed spaces B are formed. In the present embodiment, as shown in FIG. 2, two test ports 20 and 21 communicating with each closed space B are provided on the outer surfaces of the covering materials 3 to 7, respectively. With each outer surface of 7 as the test surface, it is possible to inspect the airtightness and watertightness of each closed space B on the back side of the test surface, for example, by a leak test in accordance with the foam leak test method specified in JISZ2329 It is configured.

  A manufacturing method according to an embodiment of the present invention for manufacturing the coated steel pipe 1 configured as described above will be described with reference to FIGS. FIG. 6 is a flowchart for explaining the procedure of the method for manufacturing the coated steel pipe 1. 7-18 is a figure explaining each process at the time of manufacturing the coated steel pipe 1. FIG.

  FIG. 7 is a configuration diagram showing a state in which the steel pipe 2 that has not yet been coated is rotatably mounted on the turning roll 30. FIG. 7 shows a state in which the steel pipe 2 is viewed from the pipe axis direction. The turning roll 30 has a configuration in which two supports 31 and 32 are arranged in parallel so that their longitudinal directions are perpendicular to the tube axis direction of the steel pipe 2. In FIG. 7, the support 32 overlaps the support 31 and is hidden behind the support 31. The two parallel supports 31 and 32 are arranged so as to avoid a covering portion of the outer peripheral surface of the steel pipe 2 at a predetermined interval in the pipe axis direction of the steel pipe 2. The support 31 has a configuration in which two support rolls 31b and 31c that are rotatable about a horizontal rotation axis are provided on a rectangular parallelepiped base 31a. The two support rolls 31b and 31c are disposed with their rotation axes parallel to each other and spaced apart in the longitudinal direction of the base 31a. Similarly to the support 31, the support 32 includes a rectangular parallelepiped base 32 a and two support rolls 32 b and 32 c.

  As shown in FIG. 7, the support rolls 31 b and 31 c of the support body 31 cooperate to support the steel pipe 2 rotatably at the first position in the tube axis direction, and the support rolls 32 b and 32 c of the support body 32 By cooperating and supporting the structural member 2 rotatably at the second position in the tube axis direction, the turning roll 30 can rotatably support the steel tube 2 at four points. In the present embodiment, only the support body 31 of the two support bodies 31 and 32 is provided with a drive device (not shown) that can rotate the support rolls 31b and 31c. It is possible to rotate the steel pipe 2 around the pipe axis via the support rolls 31b and 31c by a driving device. Note that this drive device may be provided only on the support body 32 or on both the support bodies 31 and 32.

  As shown in FIG. 7, in the vicinity of the steel pipe 2 placed on the turning roll 30, a covering material winding base 40 is arranged in parallel at a position facing the outer peripheral surface of the steel pipe 2. The covering material winding mount 40 includes a pallet 41 that can store a plurality of covering materials 3 to 7 horizontally, and a support column 42 that horizontally supports the pallet 41 at a height approximately equal to the diameter of the steel pipe 2. It consists of

  The manufacturing method of the coated steel pipe 1 which concerns on embodiment of this invention is started in the state shown in FIG. 7 (SP0). First, the steel roll 2 is rotated around the pipe axis by the turning roll 30 so that the portion between the predetermined positions P and Q on the outer surface of the steel pipe 2 on which the first covering material 3 is arranged is arranged on the upper side. Adjust. FIG. 8 is a view showing a state where the first covering material 3 is taken out from the pallet 41 of the covering material winding base 40. As shown in FIG. 8, the first rectangular sheet-shaped covering material 3 is taken out from the pallet 41, and this covering material 3 is placed in a predetermined position on the outer surface near the top of the steel pipe 2 along the circumferential direction of the steel pipe 2. Wrap around the part between P and Q.

  9 and 10 are enlarged views of the vicinity of the top of the steel pipe 2 around which the first covering material 3 is wound in FIG. As shown in FIG. 9, for example, one rectangular parallelepiped permanent magnet 50 is arranged on the outer surface of the steel pipe 2 so that one end side thereof is aligned with a predetermined position P in the circumferential direction of the steel pipe 2, and is adsorbed and fixed in advance. deep. The predetermined position P is an optimum position where the end portion 3D of the covering material 3 is finally disposed in the coated steel pipe 1 shown in FIGS. Similarly, predetermined positions Q to Y, which will be described later, are optimal positions where the end portions 3D to 7D and 3U to 7U of the covering materials 3 to 7 are finally arranged. In the present embodiment, the pipe shaft of the steel pipe 2 is provided at each of the predetermined positions P to Y of the portion covered by the outer surface of the steel pipe 2 so that the predetermined positions P to Y can be visually observed and the covering materials 3 to 7 can be aligned. A ruled line along the direction is marked in advance, and when the permanent magnet 50 is arranged at the predetermined position P, one end side of the permanent magnet 50 is arranged so as to be aligned with the ruled line at the predetermined position P. .

  The first covering material 3 wound around the outer surface near the top of the steel pipe 2 is moved in the direction of the magnet 50 (in the direction of the arrow 51 shown in FIG. 9) along the circumferential direction of the steel pipe 2, and its end 3D. Is brought into contact with the matching surface of the permanent magnet 50 whose one end is aligned at the predetermined position P, and the end portion 3D of the covering material 3 is aligned with this matching surface of the permanent magnet 50. By positioning in this way, the coating | covering material 3 is correctly arrange | positioned in the predetermined position P in the circumferential direction of the steel pipe 2 (SP1). In addition, the position of the coating material 3 in the tube axis direction is also arranged at a predetermined position that covers the outer surface of the steel pipe 2 by, for example, aligning with a ruled line or the like that is previously marked.

  FIG. 10 is a view showing a state in which the first coating material 3 is arranged at the predetermined position P. FIG. As shown in FIG. 10, for example, rectangular parallelepiped permanent magnets 52 and 53 are arranged on the outer surface of the covering material 3 arranged at a predetermined position P, and are attracted and fixed to the steel pipe 2 from above the covering material 3. The covering material 3 disposed at the predetermined position P is sandwiched between the steel pipe 2 and the permanent magnets 52 and 53 by the attractive force of the permanent magnets 52 and 53, and is firmly fixed to the outer surface of the steel pipe 2 (SP2). ).

  FIG. 11 is a view showing a state in which the first coating material 3 is fastened and fixed to the outer surface of the steel pipe 2 by a plurality of belts 60 from the pipe axis direction of the steel pipe 2. FIG. 12 is an enlarged view of the vicinity of the top of the steel pipe 2 to which the covering material 3 is fastened and fixed in FIG. FIG. 13 is a top view of the steel pipe 2 shown in FIG. As shown in FIG. 11, near the steel pipe 2 placed on the turning roll 30, a covering material fastening frame 70 is arranged in a position facing the outer peripheral surface of the steel pipe 2 on the side opposite to the covering material winding frame 40. It is installed. The covering material fastening stand 70 is a thick plate-like work stand 71 on which an operator can sit and work, and the work stand 71 is horizontally supported at a height of about the diameter of the steel pipe 2. It is comprised with the support | pillar 72 to do.

  As shown in FIGS. 11 to 13, a plurality of belts 60 as belt-like fastening members are wound around the outer surface of the covering material 3 temporarily fixed at a predetermined position P in the circumferential direction of the steel pipe 2. As shown in FIG. 12, a binding device 61 capable of binding to the other end of the belt 60 is provided at one end of the belt 60. Therefore, a belt wound around the steel pipe 2 in the circumferential direction using the binding device 61. Bundle 60. In the present embodiment, the bundling device 61 includes a ratchet mechanism, and when the handle 62 of the bundling device 61 is moved in the direction of the arrow 63, the belt 60 on the other end cannot be returned in the circumferential direction of the arrow 64. The belt 60 is configured to reduce the diameter of the ring formed by the belt 60 along the circumferential direction of the steel pipe 2. Utilizing this, the handle 62 is repeatedly moved in the direction of the arrow 63 by reciprocating motion, the diameter of the belt 60 wound in the circumferential direction of the steel pipe 2 is reduced, and the covering material 3 arranged at the predetermined position P is removed from the steel pipe 2. Tighten and fasten to the outer surface (SP3).

  When the handle 62 of the bundling device 61 is repeatedly moved in the direction of the arrow 63 by reciprocation, and the belt 60 on the other end side is pulled in the circumferential direction of the arrow 64, the friction between the inner surface of the belt 60 and the outer surface of the covering material 3 is obtained. Using the force, the covering material 3 is gradually moved in the circumferential direction of the arrow 64 together with the belt 60, and for example, the circumferential direction of the covering material 3 is adjusted so that the end 3U of the covering material 3 is aligned with the predetermined position Q. Adjustments may be made.

  In the present embodiment, the plurality of belts 60 that fasten and fix the covering material 3 to the outer surface of the steel pipe 2 are spaced apart from each other by a predetermined distance L over the entire length of the covering material 3 in the tube axis direction, as shown in FIG. Deploy. Further, when the covering material 3 is fastened and fixed to the outer surface of the steel pipe 2 by the plurality of belts 60, the belt 60 disposed on the center side in the tube axis direction of the covering material 3 is fastened and fixed earlier. Then, the belts 60 arranged at both ends in the tube axis direction of the coating material 3 are sequentially bound from the center side in the tube axis direction of the coating material 3 to both end sides so that the belt 60 is tightened and fixed later.

  FIG. 14 is a top view of the steel pipe 2 showing a state where the covering material 3 fastened and fixed by the plurality of belts 60 is temporarily attached to the outer surface of the steel pipe 2 by spot welding. As shown in FIG. 14, the end 3D arranged at a predetermined position P of the covering 3 fastened and fixed to the outer surface of the steel pipe 2 by a plurality of belts 60 is aligned along the pipe axis direction of the steel pipe 2 by, for example, spot welding or the like. Then, the welding is performed at a plurality of local welding points 80A discontinuously, and the outer surface of the steel pipe 2 and the inner surface of the covering material 3 are joined. Similarly, both end portions in the tube axis direction of the covering material 3 are also welded at a plurality of local welded points 80A in a discontinuous manner along the circumferential direction of the steel tube 2 by, for example, spot welding or the like. The inner surface of the covering material 3 is joined. By these spot weldings as the first welding, the covering material 3 is temporarily attached to the outer surface of the steel pipe 2 (SP4).

  In addition, when the covering material 3 is temporarily attached to the outer surface of the steel pipe 2 as described above, spot welding along the circumferential direction of both end portions of the covering material 3 is performed in a range between predetermined positions P and R. Welding between the positions Q and R should not be performed. Further, the welding of the end 3U arranged on the predetermined position Q side of the covering material 3 is not performed. This is because after the temporary attachment of the covering material 3 is finished, the end portion 4D of the second covering material 4 is inserted below the end portion 3U of the covering material 3 to a predetermined position R, and the covering material 3 and the covering material 4 are inserted. This is because an overlapping portion can be formed.

  In the present embodiment, when the covering material 3 is temporarily attached to the outer surface of the steel pipe 2 as described above, spot welding of a plurality of welding locations 80A is performed in the following order. When the end 3D of the covering material 3 is welded to the outer surface of the steel pipe 2 along the pipe axis direction, the welding is performed in the order indicated by the circled numbers in FIG. That is, first, the center position in the tube axis direction of the covering material 3 at the end portion 3D of the covering material 3 is spot welded, and then both ends in the tube axis direction of the covering material 3 at the end portion 3D of the covering material 3 are spot spotted. Weld. Next, the center positions of the first welded spot in the tube axis direction and the second welded spot at both ends in the pipe axis direction are spot welded. After that, in the same way, the center position of the welding points is selected as the next welding point, and spot welding is performed. It should be noted that welding may be performed by other procedures in a position and order in which the welding locations are uniformly distributed in the tube axis direction within the range in which welding is performed along the tube axis direction.

  When both end portions of the covering material 3 in the tube axis direction are welded to the outer surface of the steel pipe 2 along the circumferential direction, the same operation as in the case of the end portion 3D in the circumferential direction of the covering material 3 is performed. In addition, welding may be performed by other procedures in which welding locations are evenly distributed in the circumferential direction and in order as long as welding is performed along the circumferential direction.

  After the first temporary tacking of the first covering material 3 is completed, the portion of the outer surface of the steel pipe 2 to be coated has not yet been completely temporary coated, and the covering is not complete. The work of temporarily attaching the covering material 4 to the outer surface of the steel pipe 2 is started (No in SP5). FIG. 15 is a configuration diagram showing a state in which the second coating material 4 is arranged on the outer surface of the steel pipe 2. As shown in FIG. 15, the turning roll 30 rotates the steel pipe 2 around the pipe axis, and the portion between the predetermined positions R and S on the outer surface of the steel pipe 2 on which the second covering material 4 is arranged is arranged on the upper side. To adjust the position (SP6).

  After adjusting the position of the outer surface of the steel pipe 2, in order to arrange the second covering material 4 at a portion between the predetermined positions R and S of the outer surface of the steel pipe 2, a plurality of pieces wound around the outer surface of the covering material 4 The binding of the belt 60 is released (SP7). After releasing the binding of the plurality of belts 60, each end provided with the binding device 61 for the plurality of belts 60 is arranged on the work table 71 of the covering material fastening stand 70 and provided at a predetermined position on the work table 71. It is held by a holding tool (not shown). On the other hand, each other end of the plurality of belts 60 has a curved portion on the lower side of an S-shaped holder 74 suspended on a ring 73 suspended from the pallet 41 of the covering material winding base 42. Hold by.

  Next, the second covering material 4 is wound around the portion between the predetermined positions R and S on the outer surface near the top of the steel pipe 2 along the circumferential direction of the steel pipe 2. At this time, the end portion 44 </ b> D of the covering material 4 is inserted between the inner surface of the end portion 3 </ b> U of the first covering material 3 temporarily attached to the steel pipe 2 and the outer surface of the steel pipe 2. By aligning both ends 4D and 4U in the circumferential direction of the covering material 4 with the ruled lines at the predetermined positions R and S, the covering material 4 is accurately arranged at the predetermined positions R and S on the outer surface of the steel pipe 2 ( SP1). Similarly to the first covering material 3, the position in the tube axis direction is also arranged at a predetermined position. Similarly to the case of the first covering material 3, the permanent magnets 52, 53 or separate permanent magnets are attracted and fixed to the steel pipe 2 from above the covering material 4, and the covering material 4 is temporarily attached to the outer surface of the steel pipe 2. Fix (SP2). As shown in FIG. 15, a plurality of belts 60 whose both ends are held at predetermined positions after the binding is released are wound around the covering material 4 in the same manner as the case of the first covering material 3. Then, the covering material 4 arranged at the predetermined positions R and S is fastened to the outer surface of the steel pipe 2 and fastened and fixed (SP3). When tightening and fixing, the circumferential direction of the covering material 4 may be finely adjusted so that the end portion 4U of the covering material 4 is aligned with the predetermined position S in the same manner as the first covering material 3.

  FIG. 16 is a top view of the steel pipe 2 showing a state in which the covering 4 fastened and fixed by a plurality of belts 60 is spot-welded as the first welding to the outer surface of the steel pipe 2 and temporarily attached. As shown in FIG. 16, the end portion 4D of the first covering material 3 that overlaps the end portion 4D disposed at a predetermined position R of the covering material 4 fastened and fixed to the outer surface of the steel pipe 2 by a plurality of belts 60. 3U, for example, spot welding or the like, discontinuously along the pipe axis direction of the steel pipe 2 at a plurality of local welding locations 80B, and joins the outer surface of the steel pipe 2 and the inner surface of the covering material 4 and the covering material 4 And the inner surface of the covering material 3 are joined. Both ends in the tube axis direction of the covering material 4 are also welded at a plurality of local welded points 80B discontinuously along the circumferential direction of the steel tube 2 by spot welding, for example, and the outer surface of the steel tube 2 and the covering material 4 are welded. Join the inner surface. By these spot welding, the covering material 4 is temporarily attached to the outer surface of the steel pipe 2 (SP4).

  After the first temporary tacking of the second coating material 4 is finished, the portion of the outer surface of the steel pipe 2 to be coated has not yet been completed for the first temporary tacking over the entire circumference in the circumferential direction. The work of temporarily attaching the covering material 5 to the outer surface of the steel pipe 2 is started (No in SP5). By repeating the same procedure (SP6 to SP4) as the above-described second covering material, the third to fifth covering materials 5 to 7 are temporarily attached to the outer surface of the steel pipe 2.

  FIG. 17 is a configuration diagram illustrating a state in which five coating materials 3 to 7 are temporarily attached to the outer surface of the steel pipe 2. When all the five covering materials 3 to 7 are temporarily attached to the outer surface of the steel pipe 2, as shown in FIG. 17, the portion covered by the outer surface of the steel pipe 2 is subjected to primary temporary attachment over the entire circumference. Completion (Yes in SP5). After the completion of the primary tacking, the binding of the plurality of belts 60 wound around the outer surfaces of the covering materials 3 to 7 is released by the same procedure as the procedure for releasing the binding of the belt 60 described above (SP8).

  FIG. 18 is a configuration diagram showing a state in which the five temporarily attached covering materials 3 to 7 are temporarily attached to the outer surface of the steel pipe 2. After completion of the primary tacking of the five coating materials 3 to 7, as shown in FIG. 18, at the positions between the spot welded portions 80A to 80E by the primary tacking of the respective coating materials 3 to 7, In this step, spot welding is performed as additional welding, and a large number of spot welded portions 90 are formed, so that the covering materials 3 to 7 are temporarily attached to the outer surface of the steel pipe 2 (SP9). The spot welding in the temporary tacking is performed in the same procedure as the spot welding as the first welding in the primary tacking.

  In the steel pipe 2 to which the five covering materials 3 to 7 are temporarily attached, portions where the end portions 3U to 7U and 3D to 7D of the covering materials 3 to 7 are overlapped with each other along the pipe axis direction of the steel pipe 2 Then, indirect seam welding is performed, and as shown in FIG. 2, the melted joint portion 10 between the covering materials 3 to 7 and the inherent joint portion 11 between the covering materials 3 to 7 and the steel pipe 2 are hermetically formed. Next, both end portions in the pipe axial direction of the steel pipe 2 welded by indirect seam are each TIG welded along the circumferential direction of the steel pipe 2 to form an annular configuration that makes one round in the circumferential direction as shown in FIG. TIG welds 12 and 13 are hermetically formed. By the indirect seam welding and TIG welding as described above, the covering materials 3 to 7 are hermetically welded to the outer surface of the steel pipe 2 (SP10). Thereby, the closed space B is formed between the outer surface of the steel pipe 2 and the inner surfaces of the covering materials 3 to 7.

  As shown in FIG. 2, test ports 20 and 21 communicating with each closed space B formed between the inner surfaces of the respective covering materials 3 to 7 and the outer surface of the steel pipe 2 are connected to the outer surfaces of the respective covering materials 3 to 7. Attach near both ends in the tube axis direction. Each of the outer surfaces of the covering materials 3 to 7 is tested by filling each closed space B with a test gas through each of these test ports 20 and 21 or by evacuating each closed space B. As an example, the airtightness and watertightness of each closed space B on the back side of the test surface is inspected by, for example, a leak test conforming to the foam leak test method specified in JISZ2329. When a penetration defect is detected on each outer surface of the covering materials 3 to 7 by the inspection, the penetration defect is repaired and the airtightness and water tightness of each closed space B are made complete (SP11). Thus, the production of the coated steel pipe 1 covered with the covering materials 3 to 7 is completed (SP12).

  According to the above embodiment, when the coated steel pipe 1 is manufactured, every time one of the coating materials 3 to 7 is wound around the outer surface of the steel pipe in the circumferential direction, a plurality of coatings are formed on the outer surface of the wound coating material. Since the belt 60 is wound and bound in the circumferential direction, the wound covering material is fastened and fixed to the outer surface of the steel pipe 2, and then the first temporary welding is performed by the first welding. 1 covering materials 3 to 7 are brought into close contact with the outer surface of the steel pipe 2, and the volume of each closed space B formed between the outer surface of the steel pipe 2 and the inner surfaces of the covering materials 3 to 7 can be reduced as compared with the conventional case. it can. Thereby, residual air remaining in the closed space B is reduced, and the anticorrosion ability of the coated steel pipe 1 is improved. Moreover, since each coating | covering material 3-7 closely_contact | adheres to the outer surface of the steel pipe 2, the uneven | corrugated shape which arises on the outer surface of the covering steel pipe 1 reduces, and an aesthetics improves conventionally.

  Further, when the plurality of belts 60 are fastened and fixed, the plurality of belts 60 are arranged at predetermined intervals over the entire length of the coating material in the tube axis direction, and from the center side of the coating material in the tube axis direction. Since the two ends are sequentially bound and fastened and fixed, primary covering by the first welding can be performed with the covering materials 3 to 7 being in close contact with the outer surface of the steel pipe 2. The volume of the space B is reduced, and the coated steel pipe 1 with improved corrosion resistance can be manufactured. In addition, when the primary tacking of the respective covering materials 3 to 7 by the first welding is performed along the pipe axis direction or the circumferential direction of the steel pipe 2, the welding is performed within the range in which the welding in the pipe axis direction or the circumferential direction is performed. By determining the positions of the welding locations and the welding sequence so that the locations are evenly distributed, the uneven shapes generated on the outer surfaces of the respective coating materials 3 to 7 are reduced, and the appearance of the manufactured coated steel pipe 1 is improved. .

  Further, when each of the covering materials 3 to 7 is arranged on the outer surface of the steel pipe 2, the positioning work is made in contact with the permanent magnet 50 that is attracted and fixed to the outer surface of the steel pipe 2 so that the arrangement work can be performed accurately and easily. become. In addition, since the respective covering materials 3 to 7 are temporarily fixed to the outer surface of the steel pipe 2 by the permanent magnets 52 and 53, the binding work of the plurality of belts 60 is facilitated. Further, by tightening the plurality of belts 60, the respective covering materials 3 to 6 arranged at predetermined positions are moved in the circumferential direction, and the positions of the respective covering materials 3 to 6 are finely adjusted. Thus, the covering materials 3 to 6 can be accurately arranged.

  Furthermore, the coated steel pipe 1 is manufactured by rotating the steel pipe 2 around the pipe axis using the turning roll 30 and adjusting the position of the outer surface of the steel pipe 2 or the position of the covering material arranged at a predetermined position. Work is facilitated. Further, when the binding of the tightened belt-like tightening member 60 is released, the both ends of the belt-shaped tightening member that has been unfastened are held in predetermined positions, thereby facilitating the next binding operation. .

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  In embodiment mentioned above, although the case where the steel pipe 2 was comprised by the tubular shape was demonstrated, the steel pipe 2 may be comprised by shapes other than a tubular shape.

  In embodiment mentioned above, although the case where the coating | covering materials 3-7 were stainless steel was demonstrated, the coating | covering materials 3-7 may be comprised with the other metal.

  In the above-described embodiment, the case where the coated steel pipe 1 is composed of five coating materials 3 to 7 has been described. However, the coated steel pipe 1 may be composed of any number of coating materials 3 to 7. Good.

  In the above-described embodiment, the case where the first welding for the primary tacking and the second welding for the temporary tacking are spot weldings has been described. Both the first welding and the second welding are spot weldings. It may be welding other than welding. Further, two or more kinds of welding methods may be applied in combination for the first welding and the second welding.

  In the above-described embodiment, the covering materials 3 to 7 and the steel pipe 2 have been described as being welded by indirect seam welding along the pipe axis direction, but may be welded by other welding methods. Two or more kinds of welding methods may be applied in combination.

  In the embodiment described above, the covering materials 3 to 7 and the steel pipe 2 have been described as being welded by TIG welding along the circumferential direction, but may be welded by other welding methods.

  In the above-described embodiment, the case where there are two test ports 20 and 21 provided in the covering materials 3 to 7 has been described. However, one or more test ports 20 and 21 are provided in the covering materials 3 to 7. 21 may be provided.

  In the above-described embodiment, the case where the device that rotatably supports the steel pipe 2 is the turning roll 30 has been described. However, other rotation mechanisms may be used.

  In the above-described embodiment, the case where the plurality of coating materials 3 to 7 wound around the steel pipe 2 is stored in the pallet 41 has been described. However, the plurality of coating materials 3 to 7 are stored in other containers. Also good.

  In the above-described embodiment, a description is given of a case where one rectangular parallelepiped permanent magnet 50 is arranged to be attracted and fixed at a predetermined position on the outer surface of the steel pipe 2, and the end portions of the respective covering materials 3 to 7 are brought into contact with each other for positioning. However, the number of magnets arranged at a predetermined position may be two or more, and the shape of the magnets may be a shape other than a rectangular parallelepiped. The magnet may be a magnet other than a permanent magnet.

  In the above-described embodiment, the description has been given of the case where crease lines are preliminarily marked at predetermined positions P to Y along the pipe axis direction on the outer surface of the steel pipe 2, but the predetermined positions P to Y are marked by other methods. May be.

  In the above-described embodiment, the case where the covering materials 3 to 7 arranged at predetermined positions are temporarily fixed by the rectangular parallelepiped permanent magnets 52 and 53 has been described. However, the number of temporarily fixed magnets is 1 or 3 or more. The shape of the magnet may be other than a rectangular parallelepiped. The magnet may be a magnet other than a permanent magnet.

  In the embodiment described above, the case where the belt-like tightening member is the belt 60 provided with the binding device 61 at one end has been described, but the belt-like tightening member may be other than the belt.

  In the above-described embodiment, when the belt 60 is bound, the binding is performed using the binding device 61 including the ratchet mechanism. However, when the belt 60 is bound, the belt 60 may be bound by another mechanism. Good.

  In the above-described embodiment, when holding one end of the plurality of belts 60 whose binding has been released, the belt 60 is held by a holding tool (not shown) on the work table 71 of the covering material fastening rack 70 and the other end is held. Although the case where it hold | maintains using the S-shaped holder 74 was demonstrated, when hold | maintaining each both ends of the some belt 60, you may hold | maintain using another holding mechanism. Further, both end portions of the plurality of belts 60 may be held by the same method.

  In the above-described embodiment, the case where the leakage test in accordance with the foam leakage test method specified in JISZ2329 is performed and the coated outer surface of the coated steel pipe 1 is tested as a test surface has been described. The leakage test is described in JISZ2331. It may be performed in accordance with the ammonia leakage test method specified in JIS Z2333 or the helium leakage test method specified in JISZ2333, or may be performed by other methods.

  The present invention can be applied to, for example, a coated steel pipe near a tidal zone in a steel offshore structure, but is also useful for other coated steel pipes.

It is a perspective view of the covering steel pipe manufactured with the manufacturing method concerning an embodiment of the invention. It is a side view of the covering steel pipe manufactured with the manufacturing method concerning an embodiment of the invention. It is AA arrow sectional drawing of FIG. In FIG. 3, it is the figure which expanded the part with which the edge parts of a coating | covering material overlap. It is the perspective view shown about the end of the pipe | tube axis direction of the steel pipe of a coating | covering material. It is a flowchart explaining the procedure of the manufacturing method of the covering steel pipe which concerns on embodiment of this invention. It is a block diagram which shows the state by which the steel pipe which is not coat | covered was mounted on the turning roll so that rotation was possible. It is a figure which shows the state from which the 1st coating | covering material was taken out from the pallet of the coating | covering material winding stand. It is the figure which expanded the vicinity of the top part of the steel pipe around which the 1st coating | covering material was wound, and has shown the state which has contacted the 1st coating | covering material to the permanent magnet and is positioning. It is the figure which expanded the vicinity of the top part of the steel pipe around which the 1st coating | covering material was wound, and has shown the state currently temporarily fixed to the predetermined position with the 1st coating | covering material with the permanent magnet. It is the figure which showed the state by which the 1st coating | covering material was fastened and fixed to the outer surface of the steel pipe with the some belt from the pipe-axis direction of the steel pipe. In FIG. 11, it is the figure which expanded the top vicinity of the steel pipe to which the 1st coating | covering material was fastened and fixed. It is a top view of the steel pipe shown in FIG. FIG. 3 is a top view of a steel pipe showing a state in which a covering material fastened and fixed by a plurality of belts is temporarily attached to the outer surface of the steel pipe by spot welding. It is a block diagram which shows the state which has arrange | positioned the 2nd coating | covering material on the outer surface of a steel pipe. It is a top view of a steel pipe showing a state where a covering material fastened and fixed by a plurality of belts is temporarily attached to the outer surface of the steel pipe by spot welding. It is a block diagram which shows the state by which five coating | covering materials were temporarily attached to the outer surface of the steel pipe. It is a block diagram which shows the state by which five covering materials temporarily attached temporarily were temporarily attached to the outer surface of the steel pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coated steel pipe 2 Steel pipe 3-7 Coating | coated material 3D-7D, 3U-7U The edge part of the circumferential direction of a coating | coated material 10 The fusion | melting junction part by indirect seam welding 11 The intrinsic | native junction part by indirect seam welding 12, 13 TIG welding part 20 , 21 Test port 30 Turning roll 31, 32 Support body 31b, 31c, 32b, 32c Support roll 40 Coating material winding mount 41 Pallet 42 Coating material winding support column 50, 52, 53 Permanent magnet 51 Arrow 60 Belt 61 Bundling device 62 Handle 63, 64 Arrow 70 Cover material tightening mount 71 Work table 72 Cover material tightening mount column 73 Ring 74 S-shaped holder 80A-80E Spot welding spot for primary tacking 90 Spot welding for temporary tacking Location AA Cross section line B Closed space L Spacing between belts P ~ Y Outer surface of steel pipe Predetermined position in the circumferential direction

Claims (10)

A method of manufacturing a coated steel pipe in which at least a part of the outer surface of a steel pipe is covered with a plurality of coating materials over the entire circumference,
An arrangement step of arranging one of the plurality of covering materials at a predetermined position on the outer surface of the steel pipe;
A bundling step of winding a plurality of band-like fastening members around the outer surface of the covering material disposed at the predetermined position in a circumferential direction and binding the respective members, and fixing the covering material disposed at the predetermined position to the outer surface of the steel pipe; ,
A first welding step of welding a covering material fixed to the outer surface of the steel pipe to the outer surface of the steel pipe;
A binding release step for releasing the binding of the plurality of belt-like fastening members wound around the outer surface of the covering material disposed at the predetermined position;
The placement step, the bundling step, the first welding step, and the bundling release step are repeated until the outer surface of the steel pipe is covered with the plurality of covering materials over the entire circumference, and then the outer surface of the steel pipe is removed. And a second welding step of further welding the plurality of coating materials coated over the entire circumference. The method for manufacturing a coated steel pipe according to claim 1, further comprising a sealing step of sealing and welding the plurality of further welded covering materials to an outer surface of the steel pipe. In the arrangement step,
The said coating | covering material is arrange | positioned in the predetermined position of the outer surface of the said steel pipe by making it contact | abut to the magnet attracted | fixed and fixed to the outer surface of the said steel pipe, It is characterized by the above-mentioned. Manufacturing method of coated steel pipe. The binding step includes
The method according to claim 1, further comprising a temporary fixing step of placing a magnet on an outer surface of the covering material disposed at the predetermined position and temporarily fixing the covering material to the outer surface of the steel pipe by the magnetic force of the magnet. The manufacturing method of the coated steel pipe in any one. In the binding step,
The plurality of belt-like fastening members arranged at predetermined intervals over the entire length of the coating material arranged at the predetermined position in the tube axis direction are sequentially bundled from the center side to the both end sides in the tube axis direction. The method for producing a coated steel pipe according to any one of claims 1 to 4, wherein the steel pipe is fixed. In the binding step,
The tightening at the time of binding the plurality of belt-shaped tightening members respectively moves the covering material disposed at the predetermined position in the circumferential direction, and finely adjusts the position in the circumferential direction. 6. A method for producing a coated steel pipe according to any one of 5 above. In the first welding step,
When welding along the pipe axis direction of the steel pipe, discontinuous welding is performed at a plurality of local weld locations, and welding along the pipe axis direction of the steel pipe is performed at the plurality of weld locations. The method for manufacturing a coated steel pipe according to any one of claims 1 to 6, wherein the position and the welding order are determined so as to be uniformly distributed in the direction of the pipe axis. In the first welding step,
When welding along the circumferential direction of the steel pipe, discontinuous welding is performed at a plurality of local welding locations, and the plurality of welding locations are within a range where welding along the circumferential direction of the steel pipe is performed. The method of manufacturing a coated steel pipe according to claim 1, wherein the position and the welding order are determined so as to be uniformly distributed in the circumferential direction. The work is performed by rotating the steel pipe around a pipe axis and adjusting the position of the outer surface of the steel pipe or the position of the covering material disposed at the predetermined position. A method for producing a coated steel pipe as described in 1. In the binding release step,
The method for manufacturing a coated steel pipe according to any one of claims 1 to 9, wherein both end portions of the plurality of band-shaped tightening members released from the binding are respectively held at predetermined positions.

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