JP4849008B2 - Local blasting method, local blasting apparatus, method for producing welded connection tubular body, and welded connection tubular body - Google Patents

Description

  The present invention relates to a local blasting method, a local blasting apparatus for realizing the method, a method for manufacturing a welded connection tubular body using the method, and a welded connection tubular body obtained by the manufacturing method. A local blasting method for blasting only a portion of the inner surface to be blasted, a local blasting device for realizing the method, a method for manufacturing a welded connection tubular body using the method, and a welded connection obtained by the manufacturing method The present invention relates to a tubular body.

  It is required to improve the coating performance to extend the life of the steel structure, and even if the substrate is adjusted on site, a substrate adjustment equivalent to one kind of keren has been required. Yes. For example, in the steel bridge painting and anticorrosion manual (December 2005 edition), which is the standard for painting steel bridges, among the joint parts for on-site construction of new bridges, two types of keren that use power tools are also allowed for bolt joints. However, welding joints are required up to one kind of keren and are required to be blasted. Also, in the repainting of existing bridges, when durability is particularly required, up to one kind of keren is required, and blasting is required.

  As a specific example, the coating process of a U-rib steel slab will be described.

  FIG. 1 is a perspective view of a U-rib steel slab as viewed obliquely from above, and FIG. 2 is a perspective view as viewed from obliquely below.

  The U-rib steel slab 100 includes a steel slab (deck plate) 102 formed of a steel plate, a main girder (vertical girder) 104 disposed in the bridge axis direction on the lower surface of the steel slab (deck plate) 102, The main girder 106 is arranged in a direction perpendicular to the bridge axis, and U ribs (vertical ribs) 108 are arranged on the lower surface of the steel deck (deck plate) 102 in the bridge axis direction. This structure is reinforced by arranging in the direction perpendicular to the axis. The size of the U-rib steel slab 100 is about 10 m in the direction of the bridge axis and about 3 m in the direction perpendicular to the bridge axis, and a plurality of U-rib steel slabs 100 are connected to each other by welding or bolting on the road. The superstructure is formed.

  FIG. 3 is a perspective view of the connected U-rib steel plate slab 100 as viewed obliquely from above. The steel floor slabs (deck plates) 102 are connected to each other by on-site welding, and as shown in FIG. 3, an on-site weld coating portion 112 made of weld metal and a heat-affected zone is formed in the bridge axis direction and the bridge axis perpendicular direction. Has been. The weld metal is a weld bead 120 (see FIG. 6), and the heat affected zone is a portion affected by welding heat. The width of the on-site weld coating portion 112 is about 200 mm, and the end portion of the adjacent steel deck (deck plate) 102 has a width of about 100 mm as the on-site weld coating portion 112.

  As shown in FIG. 2, a hand hole 108A (length of about 200 to 300 mm × width of about 100 mm) is provided on the lower surface of the U-rib 108 positioned below the on-site weld coating portion 112. On the upper surface of the steel deck (deck plate) 102, pavement is performed after field welding to form a road surface.

  All the members constituting one U-rib steel deck 100 are welded at the factory, and the inner surface coating is done at the factory except for the part that is welded or bolted to other U-rib steel deck 100 in the field. It has been finished to finish (the outer surface can be up to undercoating). Bolt joints (for example, on-site bolt joints 114 in FIGS. 1 and 2) are unpainted or inorganic zinc-rich paint painted at the factory shipment stage. After applying two types of kelen using, undercoating and intermediate topcoating are performed.

  About the groove part of the steel floor slab (deck plate) 102 to be welded in the field, at the factory shipment stage, as shown in FIG. Is painted with inorganic zinc rich paint. This total range of about 100 mm width is the on-site weld coating portion 112, and on-site coating is performed after welding. Since this total range of about 100 mm exists at either end of the adjacent steel deck (deck plate) 102, the width of the on-site welded coating part 112 is about 200 mm, and this width is about 200 mm. Painting will be done. Of the lower surface of the steel floor slab (deck plate) 102, the inside of the U ribs other than the on-site welded coating portion 112 having a width of about 200 mm is subjected to finish coating at the factory. It is necessary to avoid scratches during field work.

  For in-situ welding of the U-rib steel plate slab 100, as shown in FIG. 5, after installing a special backing material 116 and backing material cover 118 with a back wave on the bottom surface of the steel floor plate (deck plate) 102, As shown in FIG. 6, it is common to perform submerged arc welding from the upper surface of the steel deck (deck plate) 102, and between the groove portions of the two steel decks (deck plates) 102 that perform field welding. The weld bead 120 is formed by the weld metal by submerged arc welding, and the two steel decks (deck plates) 102 are connected.

  After the on-site welding, the back wave welded portion of the bottom surface of the steel floor slab 102 of the on-site weld coating portion 112 rusts soon (this rusted back wave welded portion is referred to as a weld rust portion). Part of the groove anticorrosive agent and inorganic zinc rich paint is deformed by the influence of welding heat. For this reason, the welding rusting part and the heat affected zone on the bottom surface of the steel deck 102, that is, the on-site weld coating section 112 on the bottom surface of the steel deck 102 need to be cleaned before performing on-site coating. As described above, since it is a welded joint, up to one kind of keren is required and blasting is required. In this blasting process, it is necessary to prevent scratches on the painted parts that have been processed up to the final painting in the factory.

  On the lower surface of the steel deck 102, the on-site weld coating portion 112 in the direction perpendicular to the bridge axis crosses the vertical ribs such as the U-rib 108 and the main girder plate, and the on-site weld coating portion 112 in the bridge axis direction includes the cross beam and the horizontal rib. Is crossing. Therefore, it is necessary to sharpen the inside of the closed cross-sectional space such as the U-rib 108 as well, and it is necessary to perform one type of kelen by blasting.

  Conventionally, in a blasting process, a sheet is taped to cover a portion that is not desired to be blasted and cured. However, in order to perform this conventional curing on the inner surface of the closed cross-section space of the U-rib 108, a hand is put into the closed cross-section space of the U-rib 108 from the narrow hand hole 108A provided on the lower surface of the U-rib 108. There was only a method of performing a curing work, and it was impossible or appropriate to perform an appropriate curing. If not properly cured, there is a risk of scratching the finished paint at the factory.

  Accordingly, there is a need for a local blasting method capable of blasting only a predetermined range of the inner surface of the closed cross-sectional space of the tubular body composed of the steel deck 102 and the U rib 108 by a simple method.

  In addition, in the case of the open blasting method, it is required to install a protective cover strictly in order to prevent dust from scattering to the outside, and it is necessary to provide a large temporary structure. In addition, in the case of the open blast method, labor is also required for collecting the abrasive. In the case of the vacuum blasting method, in particular, when performing blasting for locally uneven portions, narrow portions, and specially shaped portions, time-consuming curing is required to prevent dust from being scattered to the outside.

  Patent Document 1 describes a method in which a welded portion of the outer surface of a tubular body is covered and covered with a cover guide, and the welded portion of the tubular body is vacuum blasted.

  Patent Document 2 describes a technique of performing blasting by surrounding the entire flange of a longe with a blast chamber when blasting the welded portion of the flange and the web constituting the longe.

  Patent Document 3 describes a technique in which a target member for removing rust is covered with a flexible sheet, sealed, and subjected to blasting.

JP-A-9-141555 JP 2000-135679 A JP 2004-9215 A

  However, in the method described in Patent Document 1, a hand is put in the closed cross-sectional space of the U rib from a narrow hand hole provided on the lower surface of the U-rib, and the welded portion on the inner surface of the closed cross-sectional space of the U rib is applied. It is difficult to install a cover guide.

  In the technique described in Patent Document 2, it is necessary to surround a portion to be cleaned with a blast chamber, and it is difficult to apply this technique to the inner surface of a closed cross-sectional space.

  In the technique described in Patent Document 3, it is necessary to cover and seal the target member from which rust is removed with a flexible sheet, and it is difficult to apply this technique to the inner surface of the closed section space.

  The present invention has been made in view of such problems, and it is intended to provide a local blasting method and a local blasting device capable of blasting only a predetermined range of the inner surface of a closed cross-sectional space of a tubular body by a simple method. Let it be an issue. Another object of the present invention is to provide a method for producing a welded connection tubular body using the method and a welded connection tubular body obtained by the production method.

  The present inventor has intensively researched and developed to solve the above problems, and welded rusted portions and heat affected zones on the inner surface of the welded tubular body obtained by welding and joining adjacent tubular bodies in the longitudinal direction. When blasting is performed by inserting a blast nozzle from the hand hole of the connecting tubular body, it can be easily deformed and inserted when inserted into the welded connecting tubular body from the hand hole. By disposing a pair of partition walls to be crimped to the inner wall of the welded connection tubular body so as to close a cross-sectional space inside the connection tubular body, the problem is achieved by disposing the weld rusting portion and the heat affected zone in between. The inventors have found that the problem can be solved, and have reached the present invention.

  That is, in the local blasting method according to the present invention, the welded rusted portion and the heat affected zone on the inner surface of the welded connection tubular body obtained by welding and connecting adjacent tubular bodies in the longitudinal direction, the handhole of the welded connection tubular body. When the blast nozzle is inserted from the hand hole, the blast nozzle is inserted into the welded connection tubular body so that it can be easily deformed and inserted. A pair of partition walls that are pressure-bonded to the inner wall of the welded connection tubular body so as to close a transverse cross-sectional space are disposed with the weld rusting portion and the heat affected zone in between, and the inner surface of the welded connection tubular body A blasting process can be performed only between the pair of partition walls.

  The tubular body is, for example, a tubular body made of a U-rib steel deck deck plate and a U-rib.

  If the partition wall has a function of expanding, it is easy to install the partition wall so as to close the cross-sectional space inside the welded connection tubular body, which is preferable. The partition is formed of, for example, a sponge body or an elastic ball that swells with air.

  The local blasting apparatus according to the present invention inserts a weld rust portion and a heat affected zone on the inner surface of a welded tubular body obtained by welding and joining adjacent tubular bodies in the longitudinal direction from a hand hole of the welded tubular body. In a blasting apparatus that performs a blasting process using a blasting nozzle, when inserting into the welded connection tubular body from the hand hole, it can be easily deformed and inserted into the welded connection tubular body, and a cross section inside the welded connection tubular body A pair of partition walls that are crimped to the inner wall of the welded connection tubular body so as to close the space are disposed with the weld rust portion and the heat affected zone in between, and the inner surface of the welded connection tubular body, It is characterized in that only the space between the pair of partition walls can be blasted.

  The method for manufacturing a welded tubular body according to the present invention includes a welding rust portion and a heat affected zone on the inner surface of a welded tubular body obtained by welding and joining adjacent tubular bodies in the longitudinal direction. In the method for manufacturing a welded connection tubular body in which a blast nozzle is inserted from a handhole and blasting is performed, and the welded rusted portion and the heat affected zone are coated, deformation occurs when the welded connection tubular body is inserted from the handhole into the welded connection tubular body. A pair of partition walls that are pressure-bonded to the inner wall of the welded connection tubular body so as to close a transverse cross-sectional space inside the welded connection tubular body when entering the welded connection tubular body. After arranging a rust part and a heat-affected part in between so that only the pair of partition walls can be blasted among the inner surfaces of the welded tubular body, the weld-rusted part and the heat-affected part are blast Characterized in that it sense.

  The welded connection tubular body according to the present invention can be manufactured using the method for manufacturing a welded connection tubular body.

  The local blasting method and the local blasting device according to the present invention can be easily deformed and inserted when inserted into a welded connection tubular body from a hand hole, and when the welded connection tubular body is entered, a cross section inside the welded connection tubular body. A pair of partition walls that are crimped to the inner wall of the welded connection tubular body so as to close the space are disposed with a weld rust portion and a heat affected zone in between, and the pair of partition walls among the inner surfaces of the weld connection tubular body. Since only the partition walls can be blasted, it is possible to easily perform the blasting process on the weld rusted part and the heat affected part without damaging the factory painted part or the like.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 7A is a cross-sectional view of an example of a tubular body 10 composed of a steel deck (deck plate) 102 and a U-rib 108, and FIG. 7B shows the present invention on the inner surface of the tubular body. It is a perspective view which shows the sponge body 12 which can be used suitably when implementing the local blasting method, FIG.7 (C) is the figure which compared the magnitude | size of this sponge body 12 and the sponge body 12 of a non-pressure state. FIG. 7D is a diagram showing a state in which the sponge body 12 is pressure-bonded in the U-rib 108.

  As can be seen from the shape of the sponge body 12 shown in FIG. 7B, the shape of the sponge body 12 viewed from the front is a trapezoidal shape that approximates the shape of the cross section of the U rib 108. The length of each side of the sponge body 12 in the non-pressure state when viewed from the front is such that the sponge body 12 can be pressed into the U-rib 108, and the cross-sectional shape of the tubular body 10 is as shown in FIG. In such a case, for example, 20 mm is added to the outer dimension of the cross section of the U rib 108. For this reason, as shown in FIG.7 (C), the magnitude | size of the sponge body 12 of the non-pressure state seen from the front is larger than the external shape of the cross section of a U rib. In addition, the thickness of the sponge body 12 is such that it can be self-supporting and can absorb irregularities on the inner surface of the U-rib 108, and when the cross-sectional shape of the tubular body 10 is as shown in FIG. It is.

  When the sponge body 12 is inserted into the cross-sectional space of the tubular body 10 from the hand hole 108A, and the sponge body 12 is self-supported according to the shape of the cross-sectional space of the tubular body 10, as shown in FIG. The body 12 is pressure-bonded to the inner surface of the tubular body 10, and the transverse cross section of the tubular body 10 is closed to form a partition wall.

  As described above, the on-site weld coating portion 112 having a width of about 200 mm in the lower surface of the steel deck (deck plate) 102 needs to be subjected to on-site coating by blasting.

  Therefore, in the cross-sectional space of the tubular body 10, a pair of sponge bodies 12 are arranged on both sides of the on-site weld coating portion 112, and a blast nozzle is inserted from the hand hole 108 </ b> A, and the bottom surface of the steel deck (deck plate) 102. Blast processing. Thereby, it is possible to perform local blasting treatment only on the portion of the inner surface of the tubular body 10 that is subjected to on-site coating (the on-site weld coating portion 112 having a width of about 200 mm consisting of a weld rust portion and a heat-affected zone). ) Of the lower surface of 102, the part that has been finished-painted at the factory is not scratched.

  FIG. 8 shows a situation where open blasting is performed on the field weld coating portion 112 on the inner surface of the tubular body 10 composed of the steel deck (deck plate) 102 and the U rib 108 using the local blasting method according to the present invention. It is a figure shown typically.

  In a state where the pair of sponge bodies 12 are arranged in close contact with the inner surface of the tubular body 10 on both sides of the on-site weld coating portion 112, the steel slab (deck plate) 102 faces the open blast nozzle 14 directly above. A blasting process is performed on the lower surface welding coating portion 112. For this reason, since the blasting process by the open blast nozzle 14 is performed in the space closed by the inner surface of the tubular body 10 and the pair of sponge bodies 12, the blasting material (grinding material), peeled rust, and deformed inorganic Even in the case of open blasting, zinc rich paint or the like can be prevented from being scattered outside by simply covering the periphery of the handhole 108A with a sheet or the like.

  FIG. 9 shows a situation in which vacuum blasting is performed on the on-site welded coating portion 112 on the inner surface of the tubular body 10 composed of the steel deck (deck plate) 102 and the U rib 108 using the local blasting method according to the present invention. It is a figure shown typically.

  In a state where the pair of sponge bodies 12 are arranged in close contact with the inner surface of the tubular body 10 on both sides of the on-site weld coating portion 112, the steel slab (deck plate) 102 is directed with the vacuum blast nozzle 16 facing directly above. A blasting process is performed on the lower surface welding coating portion 112.

  However, due to the structure of the vacuum blast nozzle 16, in the range of about 25 mm from the sponge body 12, the blast supply unit 16 </ b> A cannot be applied to the lower surface of the steel deck 102 in a state where the vacuum blast nozzle 16 is directed directly upward. Blasting is not possible. For this reason, in the range of about 25 mm from the sponge body 12, the vacuum blast nozzle 16 is slightly inclined, the brush mouth 16C is obliquely applied to the lower surface of the steel deck 102, and the blasting is performed obliquely with respect to the lower surface of the steel deck 102. It is necessary to spray the material.

  Even in this case, the pair of sponge bodies 12 are arranged on both sides of the on-site weld coating portion 112 in close contact with the inner surface of the tubular body 10, so that the factory coating portion is not damaged, The local blasting method according to the invention is also useful for vacuum blasting. In this case, since it is difficult to completely suck the blasting material or the like with the vacuum part 16B, the periphery of the handhole 108A is simply covered with a sheet or the like even in the blasting process using the vacuum blast nozzle 16. Keep it.

  FIGS. 10A to 10D are perspective views showing a work situation in which the sponge body 12 is installed. FIG. 10A is a perspective view showing a state before the sponge body 12 is inserted into the cross-sectional space of the tubular body 10, and FIG. 10B shows the sponge body 12 from the hand hole 108A. FIG. 10C and FIG. 10D are perspective views showing a state in which the sponge body 12 is arranged at a predetermined position in the cross-sectional space of the tubular body 10. FIG. 10C is a perspective view seen from the front direction, and FIG. 10D is a perspective view seen obliquely from below. In FIG. 10C, the U-side rib 108 and the steel slab 102 on the near side are not drawn for convenience of illustration.

  As described above, the pair of sponge bodies 12 are arranged on both sides of the on-site weld coating portion 112 in the cross-sectional space of the tubular body 10. And after performing a local blast process about the site | part weld coating part 112 about 200 mm in width which consists of a welding rust part and a heat influence part among the inner surfaces of the tubular body 10, this part is site-coated.

  In the above embodiment, the sponge body 12 is used for the partition wall when performing the local blasting process. However, any sponge body 12 can be used as long as it has a function of expanding. Here, the function of expanding is a function of having a small size (volume) when passing through the hand hole 108A and expanding the volume after passing through the hand hole 108A, thereby closing the cross-sectional space of the tubular body 10.

  For example, an elastic ball that swells in the same shape as the sponge body 12 when air is introduced can be used instead of the sponge body 12. However, the elastic ball must have a strength that does not break even when a blast material is sprayed on it.

  In addition, the blast material used for the local blasting method and the local blasting apparatus according to the present invention is not particularly limited, and alumina, garnet, or the like can be used. Further, the blast nozzle to be used may be an open blast nozzle or a vacuum blast nozzle having a size passing through the hand hole, and a commonly used known blast nozzle can be used. . The mechanism for supplying the compressed air for accelerating the blasting material and blowing it onto the object is not particularly limited, and a mechanism using a compressor (compressor) or a mechanism using a blower (blower) may be used.

Perspective view of U-rib steel slab viewed from diagonally above Perspective view of U-rib steel slab viewed from diagonally below The perspective view which looked at the connected U rib steel slab from diagonally upward A perspective view showing a groove part of a steel deck (deck plate) performing field welding Perspective view showing the backing material and backing material cover installed on the bottom of the steel deck (deck plate) Perspective view showing the situation where submerged arc welding is performed from the top of the steel deck (deck plate) (A) A cross-sectional view of an example of a tubular body composed of a steel deck (deck plate) and a U-rib, and (B) it is preferably used when the local blasting method according to the present invention is performed on the inner surface of the tubular body. The perspective view which shows the sponge body which can do, (C) The figure which compared the magnitude | size of this tubular body and the sponge body of a non-pressure state, (D) The figure which shows the state by which the sponge body was crimped | bonded in U rib The figure which shows typically the condition which is performing the open blasting about the field welding coating part of the inner surface of the tubular body which consists of a steel deck and U rib using the local blasting method which concerns on this invention. The figure which shows typically the condition which is vacuum-blasting about the field welding coating part of the inner surface of the tubular body which consists of a steel deck and U rib using the local blasting method which concerns on this invention. It is a perspective view which shows the work condition which installs a sponge body, (A) The perspective view which shows the state before inserting a sponge body in the cross-sectional space of a tubular body, (B) The cross-sectional space of a tubular body from a hand hole The perspective view which shows the state inserted in the inside, (C) The perspective view which looked at the state which has arrange | positioned the sponge body in the predetermined position in the cross-sectional space of a tubular body from the front direction, (D) Seen from the diagonally downward direction Perspective view

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Tubular body 12 ... Sponge body 14 ... Open blast nozzle 16 ... Vacuum blast nozzle 16A ... Blast supply part 16B ... Vacuum part 16C ... Brush mouth 100 ... U rib steel slab 102 ... Steel slab (deck plate)
104 ... Main digit (vertical digit)
106 ... Cross girder 108 ... U-rib 108A ... Hand hole 110 ... Horizontal rib 112 ... On-site welding coating part 114 ... On-site bolt joint 116 ... Backing material 118 ... Backing material cover 120 ... Welding bead

Claims (8)

The welding rusting portion and the heat affected zone on the inner surface of the welded connection tubular body obtained by welding the adjacent tubular bodies in the longitudinal direction are subjected to blasting by inserting a blast nozzle from the handhole of the welded connection tubular body. On the occasion
When inserted into the welded connection tubular body from the handhole, the welded connection tubular body is deformed and can be easily inserted, and when entering the welded connection tubular body, the welded connection tubular body is closed so as to close a cross-sectional space inside the welded connection tubular body. A pair of partition walls to be crimped to the inner wall of the wall, with the weld rust portion and the heat affected zone in between,
A local blasting method characterized in that, of the inner surfaces of the welded connection tubular bodies, only the space between the pair of partition walls can be blasted.   The local blasting method according to claim 1, wherein the tubular body is a tubular body including a U-rib steel deck deck plate and a U-rib.   The local blasting method according to claim 1, wherein the partition wall has a function of expanding.   The local blasting method according to claim 1, wherein the partition wall is made of a sponge body.   The local blasting method according to claim 1 or 2, wherein the partition wall is made of an elastic ball that swells with air. Blasting is performed by blasting with a blast nozzle that inserts a weld rust portion and a heat affected zone on the inner surface of a welded connection tubular body obtained by welding and connecting adjacent tubular bodies in the longitudinal direction, from a hand hole of the welded connection tubular body. In the device
When inserted into the welded connection tubular body from the handhole, the welded connection tubular body is deformed and can be easily inserted, and when entering the welded connection tubular body, the welded connection tubular body is closed so as to close a cross-sectional space inside the welded connection tubular body. A pair of partition walls to be crimped to the inner wall of the wall, with the weld rust portion and the heat affected zone in between,
A local blasting apparatus characterized in that, of the inner surface of the welded connection tubular body, only the space between the pair of partition walls can be blasted. The weld rust and heat affected zone on the inner surface of the welded tubular body obtained by welding and joining adjacent tubular bodies in the longitudinal direction were subjected to blasting by inserting a blast nozzle from the handhole of the welded tubular body Later, in the method for manufacturing a welded tubular body for coating the weld rusted portion and the heat affected zone,
When inserted into the welded connection tubular body from the handhole, the welded connection tubular body is deformed and can be easily inserted, and when entering the welded connection tubular body, the welded connection tubular body is closed so as to close a cross-sectional space inside the welded connection tubular body. A pair of partition walls that are crimped to the inner wall of the welding member are disposed with the weld rusting portion and the heat-affected zone interposed therebetween, so that only the space between the pair of partition walls can be blasted among the inner surfaces of the welded tubular body. And then blasting the weld rusted portion and the heat affected zone.   A welded connection tubular body manufactured using the method for manufacturing a welded connection tubular body according to claim 7.