JP2020019053A - Backing strip for weldment - Google Patents

Abstract

To provide a backing strip for weldment which can well conform to a base material shape, of which reduction in actual density is suppressed, and which can prevent poor welding.SOLUTION: A backing strip for weldment is strip-shaped, and is located in close proximity to a weld zone when welding plural base materials. The backing strip for weldment comprises a folding part, and plural grooves. The folding part is foldable. The plural grooves are formed in the folding part, and respectively extend in an intersection direction crossing a longer direction, and include at least one first groove having a first depth and at least one second groove having a second depth. The second depth is shallower than the first depth. At least one first groove and at least one second groove are alternately arranged in the longer direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welding backing, and more particularly to a welding backing suitable for butt welding of steel pipes.

  As a welding backing used for butt welding of steel pipes, Patent Literature 1 discloses a welding backing used for joining two rectangular steel pipes at their ends. The backing metal has a strip shape and has a bendable portion. The bent portion is bent at an angle of about 90 degrees, and is applied to the corners of the respective joint ends of the two rectangular steel pipes from the inside.

  Specifically, as shown in FIG. 6B, the welding backing metal 100 described in Patent Document 1 has a plurality of grooves 102 in a bent portion 101. The plurality of grooves 102 extend in the width direction of the backing metal 100 for welding, and are arranged at regular intervals in the longitudinal direction. Of the total thickness of the welding backing metal 100, the thickness of the remaining portion where the groove 102 is formed is smaller than 1 mm, and the remaining portion where the groove 102 is formed can be easily formed. By bending, the backing metal can be manually bent at the bent portion 101.

  Moreover, in the backing metal for welding described in Patent Document 1, since a plurality of grooves 102 are formed in the bent portion 101, the radius of curvature in each portion of the bent portion 101 can be easily adjusted, and the bent portion is formed. 101 can be favorably aligned with the corners of each joint end.

JP 2017-47462 A

  However, in the backing metal for welding described in Patent Document 1, as shown in FIG. 6B, when the bent portion 101 is bent, each groove 102 is deformed, and the volume of each groove 102 is small. Nevertheless, when added together, a relatively large volume of cavities is formed inside the backing metal 100 for welding. When a large volume cavity is formed inside the welding backing metal 100, the actual density of the material functioning as the backing metal becomes low, which may cause welding defects or welding omissions.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a backing metal for welding that can be easily bent to conform to the shape of a base material, that suppresses a decrease in actual density, and that can prevent poor welding. Is to provide.

  The welding backing metal disclosed in the present application is in the shape of a strip, and is arranged close to a welded portion when a plurality of base materials are welded to each other. The welding backing metal includes a bent portion and a plurality of grooves. The bent portion is bendable. The plurality of grooves are formed in the bent portion and each extend in a cross direction that intersects the longitudinal direction, and each of the plurality of grooves includes a first groove having a first depth and a second groove having a second depth. Include one by one. The second depth is shallower than the first depth. At least one of the first grooves and at least one of the second grooves are alternately arranged in the longitudinal direction.

  In the welding backing disclosed in the present application, the plurality of grooves further include two third grooves having a third depth. The third depth is shallower than the first depth and deeper than the second depth. The two third grooves are provided at both ends of the bent portion in the longitudinal direction.

  In the welding backing metal disclosed in the present application, the first plate thickness in the remaining portion where the first groove is formed is 0.7 to 1.8 mm in the total plate thickness.

  In the backing metal for welding disclosed in the present application, the second plate thickness in the remaining portion where the second groove is formed is 3.7 to 4.3 mm in the total plate thickness.

  In the welding backing disclosed in the present application, the width of each of the plurality of grooves is 1.0 to 2.0 mm, and the interval between two adjacent grooves among the plurality of grooves is 1.0 to 2.0 mm. 2.0 millimeters.

  In the welding backing metal disclosed in the present application, a pitch at which the first groove is formed in the bent portion is 5.7 mm or more.

  ADVANTAGE OF THE INVENTION According to the backing metal for welding of this invention, while being able to bend easily along a base material shape, the fall of actual density is suppressed and poor welding can be prevented.

It is a perspective view showing the backing metal for welding concerning an embodiment of the present invention. It is a perspective view which shows the backing metal for welding in a state different from FIG. (A) is a top view which shows the welding backing metal which concerns on embodiment of this invention. (B) is a front view which shows the welding backing metal which concerns on embodiment of this invention. It is a partial enlarged view showing the backing metal for welding concerning an embodiment of the present invention. It is a perspective view which shows the backing metal for welding at the time of use. (A) is the elements on larger scale which show the backing metal for welding which concerns on embodiment, and a welding base material. (B) is a partial enlarged view which shows the backing metal for welding which concerns on a prior art example, and a welding base material. It is the elements on larger scale which show the backing metal for welding which concerns on other embodiment of this invention. It is the elements on larger scale which show the backing metal for welding concerning other embodiment of this invention.

  Hereinafter, embodiments of a welding backing according to the present invention will be described in detail with reference to the accompanying drawings. Each embodiment described below is a preferred specific example for carrying out the present invention, and thus various technical limitations are made. However, the present invention is not limited to the particulars in the following description. Is not limited to this mode unless otherwise specified.

[Basic principle]
The basic principle of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a backing metal for welding according to an embodiment of the present invention. FIG. 2 is a perspective view showing the welding backing in a state different from that of FIG. 1. FIG. 3A is a plan view showing a backing metal for welding according to an embodiment of the present invention. FIG. 3B is a front view showing the backing metal for welding according to the embodiment of the present invention. FIG. 4 is a partially enlarged view showing a welding backing metal according to the embodiment of the present invention.

  As shown in FIG. 1, the welding backing metal 1 according to the embodiment has a strip shape, and is arranged close to a welded portion when a plurality of base materials are welded to each other. The welding backing metal 1 includes a bent portion 10 and a plurality of grooves 11. As shown in FIG. 2, the bent portion 10 is bendable, and in the embodiment, is bent at an angle of about 90 degrees. The welding backing metal 1 is formed from a material having a strength equal to or greater than that of the base material. If the base material is a rolled steel material for building structures, the welding backing metal 1 can be formed from, for example, 490N class steel.

  As shown in FIGS. 1, 3, and 4, the plurality of grooves 11 each extend in an intersecting direction X <b> 2 intersecting the longitudinal direction X <b> 1 of the welding backing metal 1, and have a first depth L <b> 1. It includes at least one groove 11A and at least one second groove 11B having a second depth L2. The plurality of grooves 11 are formed on one of the two main surfaces of the backing metal 1 for welding. The second depth L2 is shallower than the first depth L1. At least one first groove 11A and at least one second groove 11B are alternately arranged in the longitudinal direction X1. In the embodiment, the cross direction X2 is a direction orthogonal to the longitudinal direction X1. Further, the number of the plurality of grooves 11 is set to a number corresponding to the inner diameter of the corner at the joint end of the base material. For example, the number of the plurality of grooves 11 is 7 to 21.

  In the embodiment, the first depth L1 is such that, of the total thickness of the welding backing 1, the thickness of the remaining portion where the first groove 11 </ b> A is formed is equal to the welding backing 1. The thickness is set so as to be able to be bent. In the embodiment, the second depth L2 is such that even if the welding backing 1 is bent at the bent portion 10, the remaining portion of the welding backing 1 where the second groove 11 </ b> B is formed is easily formed. The thickness is set so as not to bend.

  Next, an example of use of the backing metal 1 for welding will be described with reference to FIGS. FIG. 5 is a perspective view showing the welding backing metal in use. FIG. 6A is a partially enlarged view showing a welding backing metal and a welding base material according to the embodiment. FIG. 6B is a partially enlarged view showing a backing metal for welding according to a conventional example and a welding base material.

  As shown in FIG. 5, the welding backing metal 1 is used in the embodiment when welding each end 21 of two rectangular steel pipes 20 as a welding base material. When welding each end 21 of the two rectangular steel pipes 20, the welding backing metal 1 is bent at the bent portion 10, and is applied to each end 21 from inside the rectangular steel pipe 20. When the welding backing metal 1 is applied to each end 21, the bent portion 10 is applied to a corner 21 a of each end 21. When welding is performed from the outside of the rectangular steel pipe 20 in a state where the welding backing metal 1 is applied to each end 21, the welding backing metal 1 is melted together with the base material, and the inside of the square steel pipe 20 is melted. A weld is also formed.

  As described above with reference to FIGS. 1 to 5, in the welding backing metal 1 according to the embodiment, a plurality of grooves 11 are formed in the bent portion 10 so that the welding Since there is a space margin inside the backing metal 1, the radius of curvature at each part of the bent part 10 can be easily adjusted. Therefore, the bent portion 10 can be favorably aligned with the corner 21a of each end portion 21, and the welding backing metal 1 can be favorably adapted to the base material shape.

  Moreover, in the welding backing metal 1 according to the embodiment, at least one first groove 11A and at least one second groove 11B are formed alternately in the longitudinal direction X1. Since the second depth L2 of the second groove 11B is smaller than the first depth L1 of the first groove 11A, as shown in FIG. 4, the second groove 11B is formed out of the entire plate thickness. The second plate thickness L12 in the remaining portion is larger than the first plate thickness L11 in the remaining portion where the first groove 11A is formed. That is, L12> L11.

  Since L12> L11, in the bent portion 10, the remaining portion where the second groove 11B is formed has higher rigidity than the remaining portion where the first groove 11A is formed, and is hard to bend. . Since the first groove 11A is sandwiched between hardly bendable portions, when the welding backing metal 1 is bent at the bent portion 10, as shown in FIG. Easily collapsed by ambient pressure. Therefore, when the welding backing metal 1 is bent at the bent portion 10, the first groove 11A is in a state where almost no cavity remains.

  On the other hand, when the backing metal 1 for welding is bent at the bent portion 10, the second groove 11B bends the partition wall with the first groove 11A, similar to the groove 102 of the conventional example shown in FIG. , So that the groove width decreases toward the opening side. Therefore, the volume of the second groove 11B is reduced at a rate similar to that of the conventional groove 102. In addition, since the second depth L2 of the second groove 11B is smaller than the first depth L1 of the first groove 11A, the volume of the cavity remaining inside the welding backing metal 1 for the second groove 11B is It becomes even smaller.

  As described above, by alternately arranging the first grooves 11A and the second grooves 11B, it is possible to bend the backing metal 1 for welding manually at the bent portion 10, while the first grooves 11A are formed. Can leave few cavities. Also, with respect to the second groove 11B, the volume of the cavity remaining inside the welding backing metal 1 can be reduced by the bending of the partition wall and the second depth L2 being smaller than the first depth L1. Therefore, the volume of the cavity remaining inside the welding backing 1 when the welding backing 1 is bent at the bent portion 10 can be significantly reduced, and the actual density in the welding backing 1 can be reduced. Can be suppressed, and poor welding can be prevented.

  In addition, as is clear from the above description, it is preferable to dispose the first groove 11A of the first groove 11A and the second groove 11B at both ends of the bent portion 10. The bent portion 10 is bent at an angle of about 90 degrees as a whole, mainly by bending the remaining portion where the first groove 11A is formed. Therefore, even if the second grooves 11B are arranged at both ends of the bent portion 10, the second grooves 11B arranged at both ends remain as cavities almost intact. This is because it hardly contributes to bending at an angle of degrees.

  Further, in order to reduce the volume of the cavity remaining inside the welding backing metal 1, it is conceivable to increase the number of the second grooves 11 </ b> B. However, as described above, the remaining number of the second grooves 11 </ b> B is formed. Is difficult to bend. Therefore, when the second groove 11B is provided continuously in the longitudinal direction X1, the portion where the second groove 11B is continuous hardly bends by hand. You need to use According to the welding backing metal 1 according to the embodiment, since the first grooves 11A and the second grooves 11B are provided alternately, the radius of curvature can be freely adjusted in all portions of the bent portion 10, and It is possible to conform to the shape of the base material so as to eliminate the gap with the material.

  Next, the welding backing metal 1 according to the embodiment will be described in more detail with reference to FIG. As shown in FIG. 4, the plurality of grooves 11 further include two third grooves 11C having a third depth L3. The third depth L3 is shallower than the first depth L1 and deeper than the second depth L2. The two third grooves 11C are provided at both ends of the bent portion 10 in the longitudinal direction X1.

  As described above with reference to FIG. 4, in the welding backing metal 1 according to the embodiment, the two third grooves 11 </ b> C are provided at both ends of the bent portion 10 in the longitudinal direction X <b> 1. . As described above, it is preferable to dispose the first groove 11 </ b> A which is a relatively deep groove 11 at both ends of the bent portion 10. However, both ends of the bent portion 10 are located at boundaries with the flat portion. When the radius of curvature at the boundary between the bent portion 10 and the flat portion is larger than the radius of curvature at the other portion, the backing metal 1 for welding can be made to follow the base material shape better. Therefore, by arranging the third groove 11C having the third depth L3 at both ends of the bent portion 10, it is easy to make the radius of curvature at both ends of the bent portion 10 larger than the radius of curvature at other portions. In other words, the backing metal for welding 1 can be made to better conform to the shape of the base material.

  In addition, the first plate thickness L11 in the remaining portion where the first groove 11A is formed is preferably 0.7 to 1.8 mm, out of the total plate thickness of the welding backing metal 1. It is more preferably from 0.9 to 1.6 mm, and even more preferably from 1.0 to 1.5 mm. When the first plate thickness L11 is equal to or less than the upper limit of the above range, the bent portion 10 can be easily bent so that the welding backing metal 1 can be bent by hand. When the first plate thickness L11 is equal to or larger than the lower limit of the above range, required mechanical strength can be given to the bent portion 10.

  Further, of the total thickness of the welding backing metal 1, the second thickness L12 of the remaining portion where the second groove 11B is formed is preferably 3.7 to 4.3 mm, and preferably 3 to 4.3 mm. It is more preferably from 0.8 to 4.2 mm, and even more preferably from 3.9 to 4.1 mm. When the second plate thickness L12 is equal to or larger than the lower limit value of the above range, sufficient rigidity can be given to the remaining portion where the second groove 11B is formed, and the backing metal 1 for welding at the bent portion 10 is provided. When the is bent, the first groove 11A is easily crushed, the volume of the cavity remaining inside the welding backing metal 1 is reduced, and poor welding can be prevented more effectively. When the second plate thickness L12 is equal to or less than the upper limit of the above range, when the bent portion 10 is bent, a sufficient space allowance for deformation can be given, and the backing metal 1 for welding is used as the base metal. The shape can be favorably conformed.

  Also, the width L21 of each of the plurality of grooves 11 is preferably 1.2 to 1.8 mm, more preferably 1.3 to 1.7 mm, and more preferably 1.4 to 1.6 mm. Is more preferable. Further, although it depends on the material of the backing metal 1 for welding, the interval L22 between two adjacent grooves 11 among the plurality of grooves 11 is preferably 1.2 to 1.8 mm, preferably 1.3 to 1.8 mm. It is more preferably 1.7 mm, and even more preferably 1.4 to 1.6 mm.

  By setting the width L21 to be equal to or more than the lower limit of the above range, an appropriate space margin can be given to the bent portion 10 when the welding backing metal 1 is bent at the bent portion 10; The metal 1 can be favorably aligned with the welding base material. Further, by setting the width L21 to be equal to or less than the upper limit of the above range, it is possible to prevent the volume of the cavity from increasing, and to prevent poor welding.

  Further, by setting the interval L22 to be equal to or less than the upper limit of the above range, the partition wall between the first groove 11A and the second groove 11B can be easily bent, and the cavity generated from the second groove 11B can be reduced. Further, by setting the interval L22 to be equal to or more than the lower limit of the above range, it is possible to prevent the number of the grooves 11 in the bent portion 10 from becoming too large, to reduce the cavity, and to more effectively prevent poor welding.

  The pitch L31 at which the first groove 11A is formed in the bent portion 10 is preferably 5.7 mm or more. By setting the pitch L31 in the above range, it is possible to prevent the number of the grooves 11 from becoming too large, and when the welding backing metal 1 is bent at the bent portion 10, the inside of the welding backing metal 1 An increase in the volume of the remaining cavity can be prevented, and poor welding can be better prevented. The upper limit of the pitch L31 corresponds to the use of the backing metal 1 for welding, and can be appropriately set according to the angle at which the bent portion 10 is bent.

  The embodiment of the invention has been described with reference to the drawings (FIGS. 1 to 6). However, the present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist thereof (for example, the following (1)).

(1) In the embodiment, the third grooves 11C are arranged at both ends of the bent portion 10. However, the present invention is not limited to this. The first groove 11A may be provided, and the second groove 11B may be provided as shown in FIG.

L1 first depth L2 second depth L3 third depth L11 first plate thickness L12 second plate thickness L21 groove width L22 interval between grooves L31 pitch X1 longitudinal direction X2 Cross direction 1 ... Backing metal for welding 10 ... Bending portion 11 ... Groove 11A ... First groove 11B ... Second groove 11C ... Third groove 20 ... Square steel pipe

Claims (6)

In the shape of a strip, when welding a plurality of base materials to each other, it is a welding backing metal arranged close to the welded portion,
A bendable part,
At least one of a first groove having a first depth and a second groove having a second depth shallower than the first depth is formed in the bent portion and extends in an intersecting direction intersecting the longitudinal direction. With multiple grooves including
A backing metal for welding, wherein at least one of the first grooves and at least one of the second grooves are alternately arranged in the longitudinal direction. The plurality of grooves further include two third grooves having a third depth that is shallower than the first depth and deeper than the second depth,
The welding backing metal according to claim 1, wherein the two third grooves are provided at both ends of the bent portion in the longitudinal direction.   The welding backing according to claim 1 or 2, wherein a first plate thickness in a remaining portion of the total plate thickness where the first groove is formed is 0.7 to 1.8 mm. Money.   The second plate thickness in a remaining portion of the total plate thickness where the second groove is formed is 3.7 to 4.3 mm, according to any one of claims 1 to 3. Backing metal for welding.   The width of each of the plurality of grooves is 1.0 to 2.0 mm, and an interval between two adjacent grooves of the plurality of grooves is 1.0 to 2.0 mm. The backing metal for welding according to claim 4.   The welding backing metal according to any one of claims 1 to 5, wherein a pitch at which the first groove is formed in the bent portion is 5.7 mm or more.

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