JP2014025493A - Reinforcing auxiliary implement of metal pipe line suffered from creep damage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcing auxiliary implement for a metal pipe line suffered from creep damage and provided with a blocking plug by winding a belt-like thin-plate steel plate around the metal pipe line so as to realize effective reinforcement.SOLUTION: A reinforcing auxiliary implement 1 is used for a reinforcing construction method for reinforcing a metal pipe line 2 of which an inspection hole 23 formed on a wall part is blocked by a blocking plug 24 by winding a belt plate 3 around the outer circumferential surface of the pipe line. The reinforcing auxiliary implement 1 includes: an inner circumferential side curved surface 11 which is brought into contact with the outer circumferential surface of the pipe line and has a curved shape aligned with the curvature of the outer circumferential surface of the pipe line; an outer circumferential side curved surface 12 which is formed on the outer side in the radial direction of the pipe line from the inner circumferential side contacting surface and has a curved shape formed with a curvature larger than the outer circumferential surface of the pipe line; and an accommodation hole 13 for accommodating a protrusion part which is formed toward the outer circumferential side curved surface from the inner circumferential curved surface and is protruded more than the outer circumferential surface of the pipe line on the blocking plug.

Description

  In the present invention, a metal pipe in which a creep is generated by an internal high-temperature and high-pressure fluid and a through-hole formed in a wall is closed by a plug, and a strip-shaped thin steel plate (band) is wound around the outer peripheral surface of the pipe. It is related with the reinforcement auxiliary tool used for the reinforcement construction method reinforced by doing.

  Power steam used as power for a steam turbine or the like is a high-temperature and high-pressure fluid. For example, the steam temperature is adjusted to 300 ° C. to 650 ° C., and the steam pressure is adjusted to about 5 Mpa to 8 Mpa. Since such high-temperature and high-pressure power steam flows, the pipe is deteriorated by creep.

  In order to prevent the pipe from being damaged due to creep deterioration, the pipe is reinforced. Usually, the method of cut | disconnecting the target part of piping and joining healthy piping to a cutting location is taken. However, in this method, there is a problem that work is troublesome because piping welding work and heat treatment work are involved. Therefore, in the method described in Patent Document 1, the pipe is reinforced by winding a wire around the target portion of the pipe.

JP 2011-185403 A

  In order to increase resistance to bending stress acting on the pipe, it is conceivable to wind a strip, but a plug is provided protruding from the pipe. This closing plug is attached in accordance with the radiation inspection of the pipe welded portion, and one end thereof is inserted into a through-hole penetrating the pipe and fixed by welding. And the remaining part of the obstruction | occlusion plug protrudes in the radial direction outer side from the outer peripheral surface of piping.

  Since the plug is thus protruding from the outer peripheral surface of the pipe, the band plate is wound through the tip of the plug. For this reason, the strip is separated from the outer peripheral surface of the pipe in the vicinity of the closing plug, and stress is concentrated on that portion, so that the effect is lowered.

  This invention is made | formed in view of such a situation, The objective is to perform effective reinforcement with respect to piping by which the obstruction | occlusion plug is protrudingly provided.

  In order to achieve the above-described object, the present invention provides a metal pipe in which creep is generated by an internal high-temperature and high-pressure fluid, and a through-hole formed in a wall is closed by a closing plug. A reinforcement auxiliary tool used in a reinforcement method for reinforcing by rolling a thin steel plate, and is in contact with the outer peripheral surface of the pipe, and has a curved inner peripheral side curve that is aligned with the curvature of the outer peripheral surface of the pipe A curved outer peripheral curved surface that is formed on a radially outer side of the pipe than the inner peripheral abutting surface and has a larger curvature than the outer peripheral surface of the pipe, and the inner peripheral curved surface And a storage portion that stores a protruding portion that is formed toward the outer peripheral curved surface and protrudes from the outer peripheral surface of the pipe in the plug.

  According to the reinforcing auxiliary tool of the present invention, the entire inner peripheral curved surface is brought into contact with the outer peripheral surface of the pipe, and the strip-shaped thin steel plate (strip) is brought into close contact with the outer peripheral curved surface. That is, the gap between the pipe and the strip is filled with the reinforcing aid. Thereby, the clamping force of a strip can be transmitted to the outer peripheral surface of piping via a reinforcement auxiliary tool, and the stress concentration resulting from a strip separating can be suppressed. As a result, it is possible to effectively reinforce even the piping in which the blocking plug is protruded.

  In the above-described invention, the storage portion is configured by a through-hole penetrating between the inner peripheral curved surface and the outer peripheral curved surface, and the length of the through hole is the height of the protruding portion of the closing plug. Since the band plate and the blocking plug are brought into contact with each other, the tightening force of the band plate can be applied to the blocking plug. Thereby, reinforcement with respect to the obstruction | occlusion plug can also be performed.

  In the above-described invention, when the reinforcing auxiliary tool is made of a metal having a higher creep strength than the metal constituting the pipe, the creep strength of the pipe can be increased by the reinforcement.

  In the above-described invention, when the reinforcing auxiliary tool is made of the same type of metal as that constituting the strip-shaped thin steel plate, the creep strength of the pipe can be further increased by the reinforcement.

  In the above invention, when the reinforcing auxiliary tool is formed in a strip shape in a plan view and a crescent shape in a side view, and arranged such that the long side of the strip is in the circumferential direction of the pipe, Piping can be reinforced up to the nearest to the reinforcement aid.

  In the above-described invention, when the reinforcing auxiliary tool is divided at the position of the storage portion, the reinforcing auxiliary tool can be easily attached to the pipe surface.

  According to the present invention, it is possible to effectively reinforce a metal pipe provided with a blocking plug by winding a strip-shaped thin steel plate.

It is a perspective view explaining the reinforcement auxiliary tool of a 1st embodiment. It is a longitudinal cross-sectional view explaining the reinforcement auxiliary tool of 1st Embodiment. It is a cross-sectional view explaining piping to be reinforced. It is a figure explaining a mode that a reinforcement auxiliary tool is attached. It is a transverse cross section explaining piping which attached a reinforcement auxiliary tool. It is a figure explaining a mode that a strip is wound. It is a cross-sectional view explaining piping around which a strip is wound. It is a longitudinal cross-sectional view explaining piping which wound the strip. It is a perspective view explaining other embodiment of a reinforcement auxiliary tool.

  Hereinafter, embodiments of the present invention will be described. As shown in FIGS. 1 and 2, the reinforcing auxiliary tool 1 of the present embodiment is made of a metal member that has a strip shape (rectangular shape) in plan view and a crescent shape in side view from the long side. ing.

  Here, prior to detailed description of the reinforcing auxiliary tool 1, the piping 2 to be reinforced will be described. The piping 2 shown in FIG. 3 is for flowing power steam (steam temperature = 300 ° C. to 650 ° C., steam pressure = 5 Mpa to 8 Mpa) over a long period of time in the internal space 21. Creep occurs. The pipe 2 is made of metal since high-temperature and high-pressure steam flows. Specifically, it is made of a ferritic chromium steel (for example, 9Cr-12Cr) having a low coefficient of thermal expansion.

  The diameter of the pipe 2 varies depending on the application, but is determined within a range of 200 mm to 1000 mm, for example. Moreover, the thickness of the pipe 2 is determined in the range of 40 mm to 70 mm. The diameter and thickness of the pipe 2 are determined in consideration of various conditions such as the temperature, pressure, flow rate, and flow rate of the power steam.

  Although this piping 2 is lengthened by joining single pipes by welding, the radiation inspection is performed in order to confirm that welding of the joining part is performed appropriately. This radiation inspection is performed by arranging a radiation source in the internal space 21 and detecting the radiation transmitted to the outside of the welded portion 22 (see FIG. 6). For this reason, at the time of inspection, an inspection hole 23 penetrating in the thickness direction of the pipe 2 is formed in the vicinity of the welded portion 22 (see FIG. 8).

  Since this inspection hole 23 is not used in the actual operation of the pipe 2, it is closed after the inspection is completed. The inspection hole 23 is closed by a closing plug 24. The closing plug 24 is made of a metal columnar member. One end is inserted into the inspection hole 23 and fixed to the pipe 2 by welding. The remaining portion of the plug 24 protrudes radially outward from the outer peripheral surface 25 of the pipe 2.

  Hereinafter, the reinforcing auxiliary tool 1 will be described in detail. The reinforcing auxiliary tool 1 shown in FIGS. 1 and 2 has an inner peripheral curved surface 11, an outer peripheral curved surface 12, and a storage hole 13. And this reinforcement auxiliary tool 1 is produced with the metal whose creep strength is higher than the metal (ferritic chromium steel) which comprises the piping 2. As shown in FIG. For example, it is made of austenitic stainless steel (for example, SUS304).

  The inner peripheral curved surface 11 is a portion that contacts the outer peripheral surface 25 of the pipe 2 and has a curved shape that is aligned with the curvature of the outer peripheral surface 25. In the present embodiment, the pipe 2 is configured by a curved surface corresponding to the radius R1.

  The outer peripheral curved surface 12 is a portion around which the reinforcing band plate 3 (see FIG. 6) is wound, and is formed outside the inner peripheral curved surface 11 in the radial direction of the pipe 2. The outer peripheral curved surface 12 has a curved shape having a larger curvature than the inner peripheral curved surface 11 (the outer peripheral surface 25 of the pipe 2). In the present embodiment, it is constituted by a curved surface corresponding to a radius R2 shorter than the radius R1.

  The thickness t of the reinforcement assisting tool 1 at the position where the storage hole 13 is formed (the distance between the inner peripheral curved surface 11 and the outer peripheral curved surface 12) protrudes from the outer peripheral surface 25 of the pipe 2 in the closing plug 24. The height of the portion (the protruding portion of the closing plug 24) is aligned.

  The storage hole 13 is a portion that forms a space in which the protruding portion of the closing plug 24 is stored, and corresponds to a storage portion. The storage hole 13 of the present embodiment is configured by a through-hole penetrating between the inner peripheral curved surface 11 and the outer peripheral curved surface 12. The storage hole 13 has a circular cross section, and the diameter thereof is set to be slightly larger than the diameter of the protruding portion of the closing plug 24. For this reason, a slight clearance is provided around the protruding portion housed in the housing hole 13.

  In addition, since the length of the storage hole 13 is aligned with the length of the protruding portion, the end surface of the protruding portion contacts the surface of the band plate 3 when the band plate 3 is wound. Thereby, even if the protruding portion of the blocking plug 24 tries to move away from the inspection hole 23, the movement is restricted by the band plate 3.

  Next, a method for reinforcing the pipe 2 using the above-described reinforcing auxiliary tool 1 will be described. In this example, reinforcement for the position where the closing plug 24 is formed will be described.

  In this reinforcing method, first, the reinforcing auxiliary tool 1 is attached to the pipe 2. For example, as shown in FIG. 4, the orientation of the reinforcing auxiliary tool 1 is determined so that the long side is in the circumferential direction of the pipe 2, and the storage hole 13 of the reinforcing auxiliary tool 1 is positioned at the formation position of the closing plug 24. Then, the reinforcing auxiliary tool 1 is moved to the pipe 2 side, and the inner peripheral curved surface 11 is brought into contact with the outer peripheral surface 25 of the pipe 2.

  Thereby, as shown in FIG. 5, the protruding portion of the blocking plug 24 is accommodated in the accommodation hole 13. Further, the inner peripheral curved surface 11 of the reinforcing auxiliary tool 1 contacts the outer peripheral surface 25 of the pipe 2 without a gap. Furthermore, a smoothly continuous surface is formed between both end portions of the outer peripheral curved surface 12 and the outer peripheral surface 25 of the pipe 2.

  Next, as shown in FIG. 6, the band plate 3 is wound around the outer peripheral surface 25 of the pipe 2 to which the reinforcing auxiliary tool 1 is attached. As the band plate 3, for example, a stainless steel plate having a thickness of 0.2 mm and a width of 30 to 50 mm is used. In the present embodiment, the one made of austenitic stainless steel (for example, SUS304), which is the same type of metal as the reinforcing auxiliary tool 1, is used.

  And said strip | belt board 3 is piled up and wound in multiple times in the shape of a spiral in the state which an edge part mutually overlaps. For example, the strip 3 is reciprocated in the axial direction of the pipe 2 while being spirally wound around the range L1 in which the reinforcing auxiliary tool 1 is provided. Thereby, as shown in FIG.7 and FIG.8, the reinforcement layer in which the strip 3 overlapped many times is formed. In the present embodiment, a reinforcing layer 3 ′ having a thickness of about 5 mm is formed by winding the band plate 3 25 times.

  The thus formed reinforcing layer 3 ′ (multiple strips 3) is in close contact with the outer peripheral curved surface 12 at the portion where the reinforcing auxiliary tool 1 is attached. The inner peripheral curved surface 11 is in contact with the outer peripheral surface 25 of the pipe 2 without a gap. That is, the gap between the pipe 2 and the strip 3 is filled with the reinforcing auxiliary tool 1. Thereby, the fastening force of the strip 3 can be transmitted to the outer peripheral surface 25 of the pipe 2 via the reinforcing auxiliary tool 1, and the stress concentration due to the strip 3 being separated from the outer peripheral surface 25 can be suppressed. As a result, effective reinforcement can be performed even for the pipe 2 on which the blocking plug 24 protrudes.

  Further, since the length of the storage hole 13 is aligned with the height of the protruding portion of the closing plug 24, the wound inner surface of the strip 3 and the protruding end surface of the closing plug 24 come into contact with each other. Thereby, the fastening force of the strip 3 can be applied to the closing plug 24, and the closing plug 24 can be reinforced. That is, even if the blocking plug 24 tries to move away from the inspection hole 23, this moving force can be borne by the strip 3.

  Moreover, since the reinforcement auxiliary tool 1 of this embodiment is made of a metal (austenitic stainless steel) having a higher creep strength than the metal (ferritic chromium steel) constituting the pipe 2, the reinforcement of the pipe 2 by reinforcement is performed. Strength can be increased. Furthermore, since the reinforcement auxiliary tool 1 and the strip 3 are made of the same type of metal, the creep strength of the pipe 2 can be further increased.

  In addition, the reinforcing auxiliary tool 1 is formed in a strip shape in plan view and in a crescent shape in side view, and is arranged so that the long side of the strip is in the circumferential direction of the pipe 2. The reinforcement of 2 can be performed up to the reinforcement auxiliary tool 1. Thereby, as shown in the range of the code | symbol L2 in FIG. 8, the reinforcement with respect to the welding part 22 provided in the vicinity of the reinforcement auxiliary tool 1 can be performed.

  The above description of the embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof. For example, you may comprise as follows.

  Although the reinforcement auxiliary tool 1 in the above-mentioned embodiment was comprised by the one piece as a whole, it is not limited to this structure. As shown in FIG. 9, it may be divided into two pieces 1 a and 1 b at the position of the storage hole 13. If it divides | segments in this way, when attaching the reinforcement auxiliary tool 1, it will become possible to slide each piece 1a, 1b along the surface of the piping 2. FIG. Since each piece 1a, 1b is heavy, if it can be slid along the surface of the pipe 2, it can be easily attached.

  Further, the storage hole 13 (storage portion) for storing the protruding portion of the closing plug 24 has been described by taking the through hole as an example in the above-described embodiment, but is not limited to this configuration as long as the protruding portion can be stored. For example, the hollow part by which the inner peripheral side curved surface side was open | released and the outer peripheral side curved surface side was block | closed may be sufficient.

  Moreover, regarding the material of the pipe 2, in the above-described embodiment, the pipe 2 made of high chromium steel has been described as an example, but the configuration is not limited thereto. The present invention can be applied even to a pipe 2 made of another type of metal. Similarly, the reinforcing auxiliary tool 1 and the strip 3 are not limited to austenitic stainless steel. Any metal having higher creep strength than the metal constituting the pipe 2 may be used. For this reason, you may produce the reinforcement auxiliary tool 1 and the strip 3 with a different kind of metal. In addition, the thickness and width of the strip 3 can be appropriately selected according to the pipe 2 to be reinforced.

  Moreover, regarding the use of the piping 2, it is not limited to what distribute | circulates the steam for motive power. The present invention can be applied as long as creep damage is caused by passing a high-temperature high-pressure fluid and the inspection hole 23 is closed by the closing plug 24.

DESCRIPTION OF SYMBOLS 1 ... Reinforcement auxiliary tool, 1a ... One piece in a reinforcement auxiliary tool, 1b ... The other piece in a reinforcement auxiliary tool, 11 ... Inner peripheral side curved surface, 12 ... Outer peripheral side curved surface, 13 ... Storage hole, 2 ... Reinforcement object Metal pipe, 21 ... Internal space of the pipe, 22 ... Welded part of the pipe, 23 ... Inspection hole, 24 ... Blocking plug, 3 ... Strip, 3 '... Reinforcement layer

Claims (6)

Reinforcement method that reinforces a metal pipe whose creep is generated by the internal high-temperature and high-pressure fluid and the through-hole formed in the wall is closed by a plug, by winding a strip-shaped thin steel plate around the outer peripheral surface of the pipe Reinforcing aid used for
A curved inner peripheral curved surface that is in contact with the outer peripheral surface of the pipe and is aligned with the curvature of the outer peripheral surface of the pipe;
A curved outer peripheral curved surface formed on the radially outer side of the pipe than the inner peripheral contact surface and having a larger curvature than the outer peripheral surface of the pipe;
A storage portion that is formed from the inner peripheral curved surface toward the outer peripheral curved surface and stores a protruding portion that protrudes from the outer peripheral surface of the pipe in the closing plug;
Reinforcing aids characterized by comprising: The storage portion is configured by a through-hole penetrating between an inner peripheral curved surface and the outer peripheral curved surface,
The length of the said through-hole is equal to the height of the protrusion part in the said obstruction | occlusion plug, The reinforcement auxiliary tool of Claim 1 characterized by the above-mentioned.   The reinforcement auxiliary tool according to claim 1 or 2, wherein the reinforcement auxiliary tool is made of a metal having a higher creep strength than a metal constituting the pipe.   The reinforcing auxiliary tool according to claim 3, wherein the reinforcing auxiliary tool is made of the same type of metal as the metal constituting the strip-shaped thin steel plate.   The strip according to any one of claims 1 to 4, wherein the strip is formed in a strip shape in a plan view and a crescent shape in a side view, and is arranged so that a long side of the strip is in a circumferential direction of the pipe. Reinforcing aid.   The reinforcing auxiliary tool according to claim 5, wherein the reinforcing auxiliary tool is divided at the position of the storage portion.

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