JP2021065899A - Welding method - Google Patents

Abstract

To provide a welding method for efficient welding by restraining the number of points of welding connections on a column member.SOLUTION: End parts of vertically arranged two square steel pipes 11, 12 having a plurality of erection pieces 11e, 12e are welded using a welding robot. In this case, a first step of positioning and fixing the square steel pipes 11, 12 by using the erection pieces 11e, 12e and a second step of welding first and second welding areas (Wa1, Wa2) which are areas between the adjacent erection pieces 11e, 12e and lie opposite each other with respect to a central axis C1 of the square steel pipes 11, 12 are performed. Then, a third step of removing the erection pieces 11e, 12e positioned in at least a third welding area Wa3 of third and fourth welding areas (Wa3, Wa4) sandwiched by the first welding area Wa1 and the second welding area Wa2 and a fourth step of welding the third welding area Wa3 so as to extend over the first welding area Wa1 and the second welding area Wa2 are performed.SELECTED DRAWING: Figure 3

Description

The present invention relates to a welding method for welding joint portions of column members constituting steel columns of a building.

Conventionally, a steel column of a building is constructed by joining a plurality of column members such as steel pipes in the vertical direction by welding. A welding robot may be used in the welding work of this steel pipe (see, for example, Patent Documents 1 and 2). In the welding system described in Patent Document 1, a guide rail using a corner unit having a straight portion and a curved portion is attached to the outer periphery of a square steel pipe to be welded, and a welding robot is slidably provided on the guide rail. .. Further, in the welding method described in Patent Document 2, initial welding is performed between adjacent built-in jigs at a construction site using a welding robot, and after the initial welding is completed, the built-in jigs are removed and the remaining welding is performed. And remove the erection piece after welding is completed.

A plurality of erection pieces are provided at the lower end or the upper end of the steel pipe constituting the steel frame column. These erection pieces are used for accurate alignment when joining up and down. Specifically, the upper and lower steel pipes are aligned by sandwiching a plurality of erection pieces of the upper and lower steel pipes with a splice plate or the like and holding them in a straight line. Then, the welding robot welds the upper end portion and the lower end portion of the steel pipe. In this case, when the erection piece is attached, the welding robot cannot weld the portion corresponding to the erection piece, or cannot weld with good quality.

Therefore, conventionally, when welding the ends of the square steel pipes 51 and 52 shown in FIG. 11A, the welding robot first first has two opposing corner portions Wc1 and Wc2 in which the erection pieces 51e and 52e are not provided. Is then welded, and then the remaining corner portions Wc3 and Wc4 are welded as shown in FIG. 11 (b). Then, after removing all the erection pieces 51e and 52e as shown in FIG. 11 (c), two opposing straight lines Ws1 and Ws2 are welded as shown in FIG. 11 (d), and FIG. 11 (e) ), The remaining two opposite straight portions Ws3 and Ws4 are welded.

JP-A-2018-58078 Japanese Unexamined Patent Publication No. 2018-53626

As described above, when welding a steel pipe with a welding robot, the erection piece becomes an obstacle. Therefore, welding with the erection piece installed in advance and welding with the erection piece removed after that are separated. Need to be done. For this reason, it is difficult and time-consuming to process the weld joints that occur.

The welding method for solving the above problems is a welding method in which the ends of two pillar members arranged one above the other with a plurality of erection pieces are welded using a welding robot attached to the pillar members, and the erection. A first step of aligning and fixing the upper pillar member with respect to the lower pillar member using a piece, and a region between adjacent erection pieces, which is located on the central axis of the pillar member. At least the second step of welding the first welding region and the second welding region facing each other, and the third welding region and the fourth welding region sandwiched between the first welding region and the second welding region. It includes a third step of removing the erection piece arranged in the third welding region, and a fourth step of welding the third welding region so as to extend over the first welding region and the second welding region.

According to the present invention, it is possible to suppress the number of welded joints of the column member and improve the welding work efficiency.

The perspective view explaining the attachment of the welding robot which performs the welding method of 1st Embodiment. The top view which attached the welding robot which performs the welding method of 1st Embodiment. It is explanatory drawing of the welding method in 1st Embodiment, (a) is the 1st step and 2nd step, (b) is the 3rd step, (c) is the explanatory view of the 4th step. The flow chart of the processing procedure of the evaluation processing of the validity of the welding method in 1st Embodiment. The explanatory view of the structure of the column beam frame explaining the horizontal force and the moment in the evaluation process of the validity of the welding method in 1st Embodiment. It is explanatory drawing of the welding method in 2nd Embodiment, (a) is a 1st step and 2nd step, (b) is a 3rd step, (c) is a 4th step, (d) is a 5th step. (E) is the sixth step. It is explanatory drawing of the welding method in 3rd Embodiment, (a) is a 1st step and 2nd step, (b) is a 3rd step, (c) is a 4th step. The explanatory view of the structure of the column beam frame in the case where the horizontal force is applied to other columns through the connecting beam in the first modification example. It is a plan view which showed the installation of the connecting beam in the 1st modification, (a) shows the state which the connecting beam is installed in two directions, and (b) shows the state which installed in one direction. The plan view explaining the installation state of the connecting beam which has not completed welding in the 2nd modification. It is explanatory drawing of the welding method using the conventional welding robot, (a) is the state which welds two opposing corners, (b) is a state which welds the remaining two corners, (c) is an erection piece. The removed state, (d) shows a state in which two opposing straight lines are welded, and (e) shows a state in which the remaining two opposing straight lines are welded.

(First Embodiment)
Hereinafter, the first embodiment in which the welding method is embodied will be described with reference to FIGS. 1 to 5. In this embodiment, a welding method for joining a plurality of square steel pipes in the vertical direction in order to form the same single column will be described.

FIG. 1 is a perspective view in which a guide rail 30 and a welding robot 40 are installed on a square steel pipe 12 arranged on a square steel pipe 11, and FIG. 2 is a plan view thereof.
As shown in FIGS. 1 and 2, in the present embodiment, the square steel pipes 11 and 12 to be welded have the same shape, for example, having a length of three floors. These square steel pipes 11 and 12 are annular steel pipes (square cross-section) having four-quarter arc-shaped squares. At the center of each side of the upper end and the lower end of the square steel pipes 11 and 12, erection pieces 11e and 12e are provided at the ends in the vertical direction. A plurality of through holes are formed in rows in the erection pieces 11e and 12e. The erection pieces 11e and 12e of the upper and lower square steel pipes 11 and 12 are sandwiched between the two splice plates 20 and are aligned linearly. Then, the erection pieces 11e and 12e are fixed by a bolt inserted into the through hole of the splice plate 20 and a nut screwed into the bolt. As a result, the upper and lower square steel pipes 11 and 12 are aligned in a straight line.

(Structure of guide rail and welding robot)
In the upper square steel pipe 12, a guide rail 30 is attached in the vicinity of the lower end portion. The guide rail 30 has a ring shape that surrounds the outer circumferences of the square steel pipes 11 and 12 to be welded. Specifically, the guide rail 30 includes four corner units 31 corresponding to the corners of the square steel pipes 11 and 12. Each corner unit 31 has a 1/4 circular arc-shaped curved portion corresponding to the corners of the square steel pipes 11 and 12, and two straight portions connected to both ends of the curved portion. Here, when the size of the square steel pipes 11 and 12 is large, a linear rail may be added between the corner units 31 to form a guide rail 30 that matches the size of the square steel pipes 11 and 12. .. Further, the guide rail 30 includes a plurality of mounting portions 35 arranged apart from each other on the outer periphery of the upper square steel pipe 12. The mounting portion 35 presses the tip of the bolt against the outer peripheral surface of the square steel pipe 12 by tightening the bolt, and fixes the guide rail 30 to the outer peripheral surface of the square steel pipe 12.

The welding robot 40 is slidably attached to the guide rail 30. In this embodiment, two welding robots 40 are attached to the guide rail 30. Further, as the welding robot 40, for example, "multi-layer welding robot Ishimatsu" manufactured by MHI Solution Technologies Co., Ltd. is used.

The welding robot 40 includes a carriage 41, a control cable 42, a conduit cable 44, and a welding torch 45. The dolly 41 is attached to the guide rail 30. The carriage 41 slides on the guide rail 30 via the control cable 42 at a speed corresponding to a control signal from a control device (not shown). A welding wire is penetrated in the conduit cable 44, and the welding wire to be sent is supplied to the welding torch 45. The tip of the welding torch 45 is arranged so as to face the welded portion located below the guide rail 30, and welding is performed at the welded portion using a welding wire.

(Welding method)
Next, the welding method of this embodiment will be described with reference to FIG.
First, as shown in FIG. 3A, the square steel pipe 12 is arranged and fixed on the square steel pipe 11 (first step). Specifically, the erection pieces 11e and 12e of the square steel pipes 11 and 12 are aligned with each other, sandwiched between the splice plates 20, and fixed with bolts and nuts.

Next, each welding robot 40 is used to weld the first welding region Wa1 and the second welding region Wa2 of the welding target regions of the square steel pipes 11 and 12, respectively (second step). The first welding region Wa1 and the second welding region Wa2 are regions that include square regions and are symmetrical with respect to the central axes C1 of the square steel pipes 11 and 12, respectively. The first welding region Wa1 and the second welding region Wa2 are located between the adjacent erection pieces 11e and 12e in the welding target region (entire circumference). In the present embodiment, the maximum range that can be welded by the welding robot 40 (by a normal welding operation) is set as the first welding region Wa1 and the second welding region Wa2 with the erection pieces 11e and 12e arranged.

Next, as shown in FIG. 3B, the erection pieces 11e and 12e are removed (third step). Specifically, the bolts, nuts and splice plate 20 are removed from the erection pieces 11e and 12e. Then, the erection pieces 11e and 12e are cut from the square steel pipes 11 and 12 by gas cutting or the like. In this case, the square steel pipes 11 and 12 are joined at the welded portions of the first welded region Wa1 and the second welded region Wa2. Therefore, the XX axis connecting the corners included in the first welding region Wa1 and the second welding region Wa2 becomes a weak axis.

Then, as shown in FIG. 3C, each welding robot 40 is used to weld the third welding region Wa3 and the fourth welding region Wa4, respectively (fourth step). The third welded region Wa3 and the fourth welded region Wa4 each include an angle and are opposite unwelded portions, and are adjacent ranges from the first welded region Wa1 to the second welded region Wa2, respectively.
As described above, the entire circumference of the upper end of the lower square steel pipe 11 and the lower end of the upper square steel pipe 12 is joined by welding, and the upper and lower square steel pipes 11 and 12 are integrated.

(Evaluation processing of the validity of the welding method)
Next, the validity evaluation process of the welding method will be described with reference to FIGS. 4 and 5. Here, the validity of the welding method shown in FIG. 3 is evaluated. If the validity of the welding method shown in FIG. 3 cannot be confirmed, the welding method of the second or third embodiment described later is used.

FIG. 4 is a flow chart of the processing procedure of the evaluation process of the validity of the welding method, and FIG. 5 is an explanatory diagram of the structure of the column-beam frame for explaining the calculated horizontal force P and the moment M. As shown in FIG. 5, the lower square steel pipe 11 is fixed to another column member 13 via the beam 15. Further, in this figure, the square steel pipe 12 to be welded above the square steel pipe 11 is before welding. Therefore, the square steel pipes 11 and 12 are fixed via the erection pieces 11e and 12e.

As shown in FIG. 4, first, the horizontal force P acting on the welded portion at the time of temporary installation is calculated (step S1-1). Specifically, as the horizontal force P shown in FIG. 5, the product of the horizontal seismic intensity k and the weight W of the square steel pipe 12 which is the column assembly material (shaft) is calculated. Here, for example, "0.2" is used as the horizontal seismic intensity k.

Next, the moment M acting on the welded portion at the time of temporary installation is calculated (step S1-2). Specifically, the product of the distance L from the column joint (welded portion) shown in FIG. 5 to the center of gravity of the square steel pipe 12 which is the column assembly material (shaft) and the horizontal force P is calculated as the moment M.

Next, the bending stress σ and the shear stress τ acting on the welded portion are calculated (step S1-3). Specifically, as the bending stress σ, the sum of the value obtained by dividing the moment M by the cross-sectional coefficient Z around the weak axis of the weld and the value obtained by dividing the weight W of the square steel pipe 12 by the total cross-sectional area A of the weld. Is calculated. Further, as the shear stress τ, a value obtained by dividing the horizontal force P by the total cross-sectional area A of the welded portion is calculated. Here, in the present embodiment, the cross-sectional coefficient Z around the weak axis of the welded portion is the cross section around the weak axis (XX axis) of the welded portion when the first welded region Wa1 and the second welded region Wa2 are welded. It is a coefficient, and the total cross-sectional area A of the welded portion is the total cross-sectional area of the welded portion (first welded region Wa1 and second welded region Wa2) when the first welded region Wa1 and the second welded region Wa2 are welded. ..

Then, the validity is determined (step S1-4). Specifically, when the calculated bending stress σ is equal to or less than the yield stress degree σy of the welded portion and the shear stress τ is equal to or less than the yield shear stress degree τy of the welded portion, it is determined to be appropriate. Here, as the yield stress degree σy of the welded portion and the yield shear stress degree τy of the welded portion, the yield stress degree of the base metal and the yield shear stress degree of the base metal are conventionally used. Here, the base material is a material for the square steel pipes 11 and 12.
Then, when it is determined to be appropriate, the upper end portion of the square steel pipe 11 and the lower end portion of the square steel pipe 12 are welded using the welding method of the present embodiment described above.

(Action)
After welding the first and second welding regions (Wa1, Wa2) at opposite positions, all the erection pieces 11e and 12e are removed. Then, the third and fourth welding regions (Wa3 and Wa4) between the first welding region Wa1 and the second welding region Wa2 are welded. As a result, the square steel pipe 12 is held by the welded portions of the first and second welding regions (Wa1, Wa2), so that the third and fourth welding regions (Wa3, Wa4) can be moved from the guide rail 30 to the welding robot 40. Can be welded continuously without removing. Further, when welding the third and fourth welding regions (Wa3 and Wa4), only both ends of the first and second welding regions (Wa1 and Wa2) become weld joints.

According to this embodiment, the following effects can be obtained.
(1-1) In the present embodiment, after the first welding region Wa1 and the second welding region Wa2 are welded, all the erection pieces 11e and 12e are removed, and the first welding region Wa1 and the second welding region Wa2 are connected. The third welding region Wa3 and the fourth welding region Wa4 are welded. As a result, the erection pieces 11e and 12e are removed and welded, so that the welding robot 40 can freely approach the welding region where the erection pieces 11e and 12e were located and perform welding. Further, when there are erection pieces 11e and 12e, it is necessary to perform an operation such as shaking the welding torch 45 to the left and right, but even if such an operation is not performed, the welding area where the erection pieces 11e and 12e are located can be freely used. Since welding is possible, high quality can be ensured over the entire line (entire circumference) of the welded portions of the square steel pipes 11 and 12. Further, the number of welded joints can be reduced, and the third and fourth welded regions (Wa3 and Wa4) can be continuously welded, so that the work efficiency can be improved.

(1-2) In the present embodiment, after welding the first and second welding regions (Wa1 and Wa2) at opposite positions, the third and fourth welding regions (Wa3 and Wa4) at opposite positions are formed. Weld. Since the welded regions at opposite positions are welded almost at the same time, even if the end material of the square steel pipe is shrunk due to welding, the inclination of the square steel pipes 11 and 12 can be suppressed by equalizing.

(1-3) In the present embodiment, the third and fourth welding regions (Wa3 and Wa4) are welded by the two welding robots 40, respectively. As a result, it is possible to maintain the balance at the target position and realize efficient welding.

(Second Embodiment)
Next, a second embodiment in which the welding method is embodied will be described with reference to FIG. This embodiment differs from the above embodiment only in the welding method, and is the same for the square steel pipes 11 and 12, the welding robot 40, and the like. Further, in the following embodiments, the same parts as those in the above-described embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

The welding method of the present embodiment is used, for example, when it cannot be determined that the welding method of the first embodiment is appropriate.
First, as shown in FIG. 6A, the square steel pipe 12 is arranged and fixed on the square steel pipe 11 in the same manner as in the above embodiment (first step). Then, as in the above embodiment, each welding robot 40 welds the first welding region Wa1 and the second welding region Wa2, respectively (second step).

Next, as shown in FIG. 6B, one of the two separated unwelded welded regions between the first welded region Wa1 and the second welded region Wa2 (third welded region Wa3). ) Are removed (third step). In this case, the XX line in the figure is the weak axis.

Then, as shown in FIG. 6C, one (first) welding robot 40 welds the third welding region Wa3. In this case, in the present embodiment, initial welding for welding the central axis side portion Wf3 in the third welding region Wa3 is executed (fourth step). The central axis side portion Wf3 is a portion obtained by welding several layers on the central axis C1 side (opposite side of the welding robot 40) in the third welding region Wa3, and extends from the first welding region Wa1 to the second welding region Wa2. The range. The central axis side portion Wf3 is a portion where the total cross-sectional area A of the welded portion totaled with the first and second welded regions (Wa1 and Wa2) becomes an area that can be determined to be appropriate in step S1-4.

Then, as shown in FIG. 6D, after the welding of the central shaft side portion Wf3 is completed, the remaining erection pieces 11e and 12e are removed from the square steel pipes 11 and 12 (fifth step). In this case, the YY line in the figure is the weak axis.

Next, as shown in FIG. 6E, the remaining third welding region Wa3 is welded using the first welding robot 40. Further, another (second) welding robot 40 is used to weld the fourth welding region Wa4 (sixth step). Here, the fourth welded region Wa4 is an unwelded region arranged at a position facing the third welded region Wa3, and is a range extending from the first welded region Wa1 to the second welded region Wa2.
As described above, the entire circumference of the upper end of the lower square steel pipe 11 and the lower end of the upper square steel pipe 12 is joined by welding, and the upper and lower square steel pipes 11 and 12 are integrated.

(Action)
The erection pieces 11e and 12e in the third welding region Wa3 are removed, and the central axis side portion Wf3 of the third welding region Wa3 is initially welded. At the time of this initial welding, the square steel pipe 12 can be held by the welded portions in the first and second welding regions (Wa1, Wa2) and the two erection pieces 11e and 12e. Further, after the initial welding of the central shaft side portion Wf3 is completed, the erection pieces 11e and 12e are removed and the fourth welding region Wa4 is welded. At the time of this welding, the square steel pipe 12 can be held at the first and second welding regions (Wa1, Wa2) and the central axis side portion Wf3 of the third welding region Wa3.

According to this embodiment, in addition to the same effect as in (1-2) above, the following effects can be obtained.
(2-1) In the present embodiment, in the initial welding of the third welding region Wa3, the square steel pipe is formed by the welded portions in the first and second welding regions (Wa1, Wa2) and the two erection pieces 11e and 12e. Holds 12. Further, when the fourth welding region Wa4 is welded, the square steel pipe 12 can be held between the first and second welding regions (Wa1, Wa2) and the central axis side portion Wf3 of the third welding region Wa3. As a result, safety can be ensured, the occurrence of welded joints can be suppressed, the quality of the welded portion can be ensured, and continuous and efficient welding can be performed.

(2-2) In the present embodiment, the first welding robot 40 welds the third welding region Wa3. Then, after the initial welding of the central axis side portion Wf3 of the third welding region Wa3 is completed, the second welding robot 40 welds the fourth welding region Wa4. As a result, the waiting time of the second welding robot 40 for welding the fourth welding region Wa4 can be shortened, and the entire circumference of the square steel pipes 11 and 12 can be welded in a short time.

(Third Embodiment)
Next, a third embodiment in which the welding method is embodied will be described with reference to FIG. 7. This embodiment differs from the square steel pipes 11 and 12 of the above embodiment only in the position where the erection piece is provided.

As shown in FIG. 7, in the square steel pipes 21 and 22 of the present embodiment, the erection pieces 21e and 22e are provided at positions closer to the two opposite corners than the center.
In the present embodiment, with the erection pieces 21e and 22e provided, the positions of the erection pieces 21e and 22e that can be determined to be appropriate in steps S1-4 are specified. For example, the positions of the erection pieces 21e and 22e are specified so that the shear stress τ based on the total cross-sectional area A of the first welded region Wb1 and the second welded region Wb2 is equal to or less than the yield shear stress degree τy of the welded portion. Here, the first welding region Wb1 and the second welding region Wb2 include corners, respectively, and are symmetrical with respect to the central axis C1 of the square steel pipes 21 and 22, similar to the first welding region Wb1 and the second welding region Wb2. This is the maximum range region in which the welding robot 40, which is provided at the opposite positions and is located between the adjacent erection pieces 11e and 12e, can weld (by a normal welding operation).

Then, in the present embodiment, welding is performed in the same manner as in the first embodiment.
Here, as shown in FIG. 7A, the square steel pipe 22 is arranged and fixed on the lower square steel pipe 21 (first step). Specifically, the erection pieces 21e and 22e of the square steel pipes 21 and 22 are aligned with each other, sandwiched between the splice plates 20, and fixed with bolts and nuts.

Next, each welding robot 40 welds the first welding region Wb1 and the second welding region Wb2, respectively (second step). In this case, since the erection pieces 21e and 22e are separated from each other as the first welding region Wb1 and the second welding region Wb2 as compared with the first embodiment, a continuous wide welding region can be secured.

Next, as shown in FIG. 7B, the erection pieces 21e and 22e are removed (third step). In this case, the square steel pipes 21 and 22 are joined at the welded portions of the first welded region Wb1 and the second welded region Wb2.

Then, as shown in FIG. 7C, each welding robot 40 welds the third welding region Wb3 and the fourth welding region Wb4, respectively (fourth step). The third welded region Wb3 and the fourth welded region Wb4 each include an angle and are opposite unwelded portions, and are in the range from the first welded region Wb1 to the second welded region Wb2, respectively.
As described above, the entire circumference of the upper end of the lower square steel pipe 11 and the lower end of the upper square steel pipe 12 is joined by welding, and the upper and lower square steel pipes 11 and 12 are integrated.

(Action)
Since the positions of the erection pieces 21e and 22e are shifted, when welding the third and fourth welding regions (Wb3, Wb4), the square steel pipe is formed at the welded portion formed in the first and second welding regions (Wb1, Wb2) having a large area. 12 can be held.

According to this embodiment, in addition to the same effects as (1-2) and (1-3) above, the following effects can be obtained.
(3-1) In the present embodiment, the positions of the erection pieces 21e and 22e are shifted to increase the areas of the first welding region Wb1 and the second welding region Wb2 to be welded, and the third and fourth welding regions (Wb3) are increased. , Wb4) are welded. As a result, the bending stress σ and the shear stress τ of the welded portion can be reduced, and the safety at the time of temporary installation can be enhanced. Alternatively, even if it is not determined to be appropriate in the first embodiment, appropriate welding can be performed in the present embodiment. Further, since the number of welded joints can be reduced, the quality of the welded portions of the square steel pipes 11 and 12 can be ensured, and the third and fourth welded regions (Wb3 and Wb4) can be continuously and efficiently welded. it can.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the welding method according to the first embodiment, the bending stress σ calculated in the validity determination process (step S1-4) is equal to or less than the yield stress degree σy of the welded portion, and the shear stress τ is the welded portion. When the yield shear stress degree was τy or less, it was judged to be appropriate. Here, the upper square steel pipe 12 is connected to another column via a connecting beam, and the horizontal force P acting on the square steel pipe 12 is borne by the other column to perform the welding method of the first embodiment. You may.

Specifically, as shown in FIG. 8, the square steel pipe 12 is connected to the adjacent column member 14 via the connecting beam 16. The column member 14 is joined to the lower column member 13 at the welded portion Cp1. The column member 13 is fixed by the square steel pipe 11 and the beam 15. The column members 13 and 14 may be fixed by using the erection pieces of the column members 13 and 14 instead of the welded portion Cp1.

Here, as shown in FIG. 9, the connecting beam 16 is provided in the square steel pipe 12 so that the horizontal force P can be transmitted in the weak axis (XX-ray) direction of the square steel pipes 11 and 12 to be welded. .. FIG. 9A shows a state in which the connecting beam 16 is installed in two directions. Here, the connecting beam 16 may be either a main beam or a temporary beam. Further, in the case of a temporary beam or the like, as shown in FIG. 9B, the connecting beam 16 is installed in one direction at the corner of the square steel pipe 12 via the connecting beam 16 from the adjacent column member. May be good. Then, after welding the first and second welding regions (Wa1, Wa2), the horizontal force P acting on the square steel pipe 12 is applied to the column members 14 and 13 via the connecting beam 16, and the erection piece 11e , 12e are removed, and the third and fourth welding regions (Wa3 and Wa4) are welded. As a result, the connecting beam 16 can bear the horizontal force P.

Further, as shown in FIG. 10, the first and second welded regions (Wa1, Wa2) in the square steel pipes 11 and 12 connected by the connecting beam 16 are set with respect to the vertical plane located in the middle between the adjacent columns. Place in a position that is plane symmetric. Further, the second welding region Wa2 is arranged at a position facing two adjacent columns. As a result, the weak axis direction of the welded portion of the square steel pipes 11 and 12 can be rotated by 90 degrees, so that the weak points can be compensated for by the adjacent square steel pipes 12. In this case, when welding the square steel pipes 11 and 12, the welding of the adjacent square steel pipes 11 and 12 may be incomplete, or the erection pieces 11e and 12e may be removed.

In the second embodiment, after the central axis side portion Wf3 of the third welding region Wa3 is welded, the remaining erection pieces 11e and 12e are removed, and the fourth welding region Wa4 is welded. When welding with one welding robot 40, the fourth welding region Wa4 may be welded after all the third welding regions Wa3 are welded and the remaining erection pieces 11e and 12e are removed.

-In each of the above embodiments, in the first step, the erection pieces 11e, 12e, 21e, 22e of the square steel pipes 11, 12, 21, 22 were aligned and fixed using the splice plate 20, bolts and nuts. The method of aligning and fixing the square steel pipe 12 with respect to the square steel pipe 11 by using the erection pieces 11e, 12e, 21e, 22e is not limited to the case of using the splice plate 20. For example, instead of the splice plate 20, a known dedicated steel frame construction jig (dedicated construction tool) for fixing the erection pieces 11e, 12e, 21e, 22e to each other may be used.

-In each of the above embodiments, one erection piece 11e, 12e, 21e, 22e is provided on each side of the square steel pipes 11, 12, 21, and 22. The number of erection pieces is not limited to one. For example, depending on the size and shape of the square steel pipes 11 and 12, it may be applied to a square steel pipe provided with a plurality of erection pieces on each side. In this case, as a second step, the first welding region and the second welding region, which are located between the adjacent erection pieces and are arranged at opposite positions, are welded. Here, when the erection pieces are not evenly arranged, it is preferable to weld the welded portion having a larger area as the first welding region and the second welding region. Further, the first welding region and the second welding region may be regions that do not include corners. Then, the erection piece in at least one of the two unwelded regions from the first welded region to the second welded region is removed, and welding is performed. Even in this case, the number of welded joints can be reduced.

-In each of the above embodiments, the joint portions of the square steel pipes 11, 12, 21, and 22 were welded using two welding robots 40. The number of welding robots 40 is not limited to two, and may be one.
-In each of the above embodiments, the ends of the square steel pipes 11, 12, 21, 22 arranged one above the other were welded. The column member for welding the upper end portion and the lower end portion arranged above and below is not limited to the square steel pipe. For example, it can also be used when a column member of a circular steel pipe or a welded assembly box type cross-section column is welded up and down. Here, the circular steel pipe is usually fixed by using four erection pieces at equal intervals. Therefore, welding regions between adjacent erection pieces at opposite positions are welded as a first welding region and a second welding region (second step). Then, the erection piece is removed (third step), and the third and fourth welding regions extending from the first welding region to the second welding region are welded (fourth step). Even in this case, the number of welded joints can be reduced and welding can be performed efficiently.

-In each of the above embodiments, the validity evaluation process of the welding method is executed. You may let the computer perform this process. In this case, various values (horizontal seismic intensity k, weight W of the square steel pipe 12, distance L, cross-sectional coefficient Z around the weak axis of the welded portion, first welding region Wa1 and second welding region Wa2 are totally cut off by the computer. Enter the area A). Then, the computer calculates the moment M, the bending stress σ, and the shear stress τ, compares the yield stress degree σy and the yield shear stress degree τy, executes the validity judgment process, and outputs the validity judgment result. ..

Next, the technical idea that can be grasped from the above embodiment and another example will be added below.
(A) In the third step, only the erection piece arranged corresponding to the third welding region is removed.
In the fourth step, in the third welding region, initial welding is performed by welding the portion on the central axis side so as to extend from the first welding region to the second welding region.
After the completion of the initial welding, a fifth step of removing the erection piece arranged in the fourth welding region, and
The welding method according to claim 1, further comprising a sixth step of welding the fourth welding region.

C1 ... Central axis, Cp1 ... Welded portion, Wa1, Wb1 ... First welded area, Wa2, Wb2 ... Second welded area, Wa3, Wb3 ... Third welded area, Wa4, Wb4 ... Fourth welded area, Wc1, Wc2 Wc3, Wc4 ... Square part, Wf3 ... Central axis side part, Ws1, Ws2, Ws3, Ws4 ... Straight part, 11,12,21,22,51,52 ... Square steel pipe, 13,14 ... Pillar member, 11e, 12e , 21e, 22e, 51e, 52e ... Election piece, 15 ... Beam, 16 ... Connecting beam, 20 ... Splice plate, 30 ... Guide rail, 31 ... Corner unit, 35 ... Mounting part, 40 ... Welding robot, 41 ... Cart, 42 ... control cable, 44 ... conduit cable, 45 ... welding torch.

Claims (5)

It is a welding method in which the ends of two pillar members arranged above and below with a plurality of erection pieces are welded by using a welding robot attached to the pillar members.
The first step of using the erection piece to align and fix the upper pillar member with respect to the lower pillar member, and
A second step of welding the first welding region and the second welding region, which are regions between adjacent erection pieces and face the central axis of the column member.
A third step of removing the erection piece arranged at least in the third welding region of the third welding region and the fourth welding region sandwiched between the first welding region and the second welding region.
A welding method comprising a fourth step of welding the third welding region so as to extend over the first welding region and the second welding region. In the third step, all the erection pieces provided in the third welding region and the fourth welding region are removed.
The welding method according to claim 1, wherein in the fourth step, the fourth welding region facing the third welding region is welded together with the third welding region. Two of the welding robots are attached to the pillar member.
In the second step, the welding robot welds the first welding region and the second welding region, respectively.
The welding method according to claim 1 or 2, wherein the welding robot welds the third welding region and the fourth welding region, respectively. The column member is a square steel pipe and
The claim is characterized in that the erection piece is arranged at a position closer to the corner of the third welding region than the center of each side so that the first welding region and the second welding region become larger. The welding method according to any one of 1 to 3. The welding method according to any one of claims 1 to 4, wherein the upper column member is fixed to another column via a connecting beam prior to the third step.

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