Welding structure and welding method

Abstract

To provide a method to suppress diffusion of spark, odor, dust, etc. from occurring during welding.SOLUTION: Provided is a welded structure 1 including: a steel material 2; a plate 4 attached with a welding space W between the plate and the steel material 2; a bar (stud bolt 3) a tip 3a of which is welded to the steel material 2; and a ferrule 5 disposed at a portion of the tip of the bar (stud bolt 3). The welded structure has a closing part (fire-resistant material) for closing the welding space between the steel material 2 and the plate 4, the plate 4 has an insertion hole 4a with a diameter wider than the bar (stud bolt 3) for inserting the bar (stud bolt 3), and a gap between the bar and the insertion hole is filled with a fire-resistant / heat-resistant insulation material 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a welded structure and a welding method. [Background technology]

[0002] Welding work is generally involved in the reinforcement of steel structures. Such welding work is performed, for example, by a welding device such as that disclosed in Japanese Patent Laid-Open Publication No. 2003-236611. That is, this welding device attaches a stud bolt to the chuck of a welding gun and stud-welds the stud bolt to the welding target by arc welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-68089 A [Patent Document 2] JP 2013-35058 A [Patent Document 3] Japanese Patent Application Publication No. 5-237660 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when welding work is performed using such welding equipment, sparks, odors, dust, etc. are generated, which may lead to fires due to sparks, unpleasant odors that may be felt by third parties, and health damage due to dust.

[0005] Furthermore, Patent Documents 2 and 3 describe welding jigs that suppress the spread of sparks and the like, but these are applied to capacitor-type stud welding, which uses a smaller current during discharge compared to the arc type and has a shorter welding time, and are not suitable for arc-type stud welding.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to suppress the diffusion of sparks, odors, dust, and the like that are generated during welding (arc welding). [Means for solving the problem]

[0007] The present invention, which is a main object of the present invention to achieve the above object, is a welded structure having a steel material, a plate material attached to the steel material with a weld space therebetween, a bar material having a tip welded to the steel material, and a ferrule provided at the tip of the bar material, the welded structure having a closing part that closes the weld space between the steel material and the plate material, the plate material has an insertion hole having a diameter larger than that of the bar material, and the bar material is inserted through the insertion hole, and the gap between the bar material and the insertion hole is filled with a fire-resistant and heat-resistant insulating material. The fire-resistant and heat-resistant insulating material has an outer diameter portion smaller than the insertion hole, and an outer diameter portion connected to the smaller outer diameter portion and larger than the insertion hole, the smaller outer diameter portion being inserted into the insertion hole, and the larger outer diameter portion being in contact with the plate material. A welded structure characterized by It is.

[0008] Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. Effect of the Invention

[0009] According to the present invention, it is possible to suppress the diffusion of sparks, odors, dust, and the like that are generated during welding. [Brief description of the drawings]

[0010] [Figure 1] 1A and 1B are a schematic cross-sectional view and a schematic plan view of a welded structure 1. [Diagram 2] FIG. 4 is an explanatory diagram for explaining a welding method. [Diagram 3] 1 is a flowchart of a welding method. [Figure 4] FIG. 11 is a schematic cross-sectional view of a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] At least the following matters will become apparent from this specification and the accompanying drawings.

[0012] A welded structure comprising a steel material, a plate material attached to the steel material with a weld space therebetween, a bar material having a tip welded to the steel material, and a ferrule provided at the tip of the bar material, the welded structure having a blocking portion that blocks the weld space between the steel material and the plate material, the plate material having an insertion hole with a diameter larger than that of the bar material through which the bar material passes, and the gap between the bar material and the insertion hole is filled with a fire-resistant and heat-resistant insulating material.

[0013] According to this type of welding structure, the welding space becomes a closed space due to the blocking portion that blocks the welding space and the fire-resistant and heat-resistant insulating material that fills the gap between the rod material and the insertion hole, and further, by installing a ferrule, it is possible to suppress the diffusion of sparks, odors, dust, etc. that are generated during welding.

[0014] In such a welded structure, it is desirable that the ferrule has a surrounding portion that surrounds the bar material and is accommodated in the insertion hole, and an abutment portion that is wider in diameter than the surrounding portion, is connected to the surrounding portion, and abuts against the steel material.

[0015] According to this type of welding structure, since the surrounding portion is accommodated in the insertion hole, the position of the ferrule is less likely to shift compared to when it is not accommodated, and the position of the rod material surrounded by the ferrule is also less likely to shift, so that shifting of the welding position can be suppressed.

[0016] In such a welded structure, it is preferable that the bar material is stud-welded to the steel material, and the plate material has a gas filling hole for filling with gas.

[0017] According to such a welding structure, a rare gas or the like can be sealed in the welding space during welding, so that deterioration of the welding quality can be suppressed.

[0018] a plate material attachment step of attaching the plate material to the steel material such that a welding space is provided between the steel material and the plate material and the ferrule is positioned within the welding space; a blocking portion forming step of forming a blocking portion that blocks the welding space between the steel material and the plate material; a fire-resistant and heat-resistant insulating material installation step of installing a fire-resistant and heat-resistant insulating material in the insertion hole; a rod material insertion step of inserting the rod material into the insertion hole and the ferrule; and a rod material welding step of welding the tip of the rod material to the steel material in a state in which the ferrule is provided at a tip of the rod material and the gap between the rod material and the insertion hole is filled with the fire-resistant and heat-resistant insulating material.

[0019] According to this welding method, the welding space becomes a closed space due to the blocking portion that blocks the welding space and the fire-resistant and heat-resistant insulating material that fills the gap between the rod material and the insertion hole, and further, the installation of the ferrule makes it possible to suppress the diffusion of sparks, odors, dust, etc. that are generated during welding.

[0020] In such a welding method, it is desirable that the ferrule comprises a surrounding portion and an abutment portion which is wider in diameter than the surrounding portion and connected to the surrounding portion, and in the ferrule installation process, the ferrule is installed on the plate material by accommodating the surrounding portion in the insertion hole, in the plate material attachment process, the plate material is attached so that the abutment portion abuts against the steel material, and in the bar material welding process, the tip of the bar material is welded to the steel material with the surrounding portion surrounding the bar material.

[0021] According to this welding method, since the surrounding portion is accommodated in the insertion hole, the position of the ferrule is less likely to shift compared to when it is not accommodated, and the position of the rod material surrounded by the ferrule is also less likely to shift, so that it is possible to suppress shifting of the welding position.

[0022] Such a welding method further includes a gas filling hole forming step of forming a gas filling hole in the plate material for filling with gas, and a gas filling step of filling the gas through the gas filling hole, and in the bar welding step, it is preferable that the tip of the bar material is stud welded to the steel material with gas filled in the welding space.

[0023] According to this welding method, since a rare gas or the like can be sealed in the welding space during welding, deterioration of the welding quality can be suppressed.

[0024] ===This embodiment=== A welded structure 1 according to this embodiment will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view and a schematic plan view of the welded structure 1, where the upper figure is a schematic cross-sectional view and the lower figure is a schematic plan view seen from below.

[0025] The welded structure 1 according to this embodiment is a welded structure 1 in which a stud bolt 3 (corresponding to a rod material) is arc stud welded (hereinafter also simply referred to as welding) to a steel material 2 by the arc method, and includes the steel material 2, the stud bolt 3 having a tip 3a (upper end) welded to the steel material 2, a plate material 4 attached to the steel material 2 with a welding space W therebetween, a ferrule 5 provided at the tip 3a (upper end) of the stud bolt 3, a fire-resistant and heat-resistant insulating material 6, a gas filling hole 7, and a gas suction hole 9.

[0026] Although FIG. 1 shows an example in which the upper end surface of the stud bolt 3 is stud-welded to the underside of the steel material 2, this is not limited to this example, and the top and bottom may be upside down, or the steel material 2 may be on the left side (right side) and the stud bolt 3 on the right side (left side).

[0027] The steel material 2 is a structural material for a building or the like, and may be, for example, a steel beam using an H-shaped steel beam.

[0028] The stud bolt 3 is a bolt for attaching a plate material 4 to a steel material 2 as a reinforcing material. The upper end surface of the stud bolt 3 is in contact with the lower surface of the steel material 2, and an arc is generated from this state to weld the stud bolt 3 to the steel material 2. During welding, an arc welding device (not shown) is set below the stud bolt 3, and the stud bolt 3 is welded to the steel material 2 by starting the arc welding device.

[0029] The plate material 4 is a reinforcing material for reinforcing the steel material 2, and has a substantially rectangular shape in a plan view. As described above, the plate material 4 is attached to the steel material 2 with a weld space W therebetween.

[0030] Moreover, the plate material 4 has a concave shape in a cross-sectional view, and the left end and the right end protrude upward. Such protrusions are provided on the entire outer periphery of the plate material 4, and in Fig. 1, it is possible to make the welding space W a closed space. In other words, the plate material 4 has a protrusion (corresponding to a closing portion) that closes the welding space W between the steel material 2 and the plate material 4.

[0031] 1, in this embodiment, in order to firmly attach the plate material 4 to the steel material 2, the plate material 4 and the steel material 2 are clamped and fixed with a clamp-like object. However, this is not limited to this, and for example, a method in which an operator presses them firmly together, or a method in which the attractive force of electromagnets is used to attach them together, etc. can also be used.

[0032] The plate material 4 has, in the center in a plan view, an insertion hole 4a with a diameter larger than that of the stud bolt 3, through which the stud bolt 3 is inserted. In other words, the insertion hole 4a is a hole that passes through the plate material 4 in the vertical direction, and the upper end surface of the stud bolt 3 passes through the insertion hole 4a from outside the welding space W and contacts the lower surface of the steel material 2.

[0033] The ferrule 5 is made of a heat-resistant ceramic and has a function of shielding the generated arc from the air, a function of acting as a mold for the molten metal, a function of keeping the temperature so that the wire does not cool too rapidly, and the like.

[0034] Moreover, the ferrule 5 has a substantially circular shape in a plan view, and has a surrounding portion 5a that surrounds the stud bolt 3 and is housed in the insertion hole 4a, and an abutting portion 5b that has a larger diameter than the surrounding portion 5a, is connected to the surrounding portion 5a, and abuts against the steel material 2. In other words, the ferrule 5 has at least a portion with an outer diameter smaller than the insertion hole 4a and a portion with an outer diameter larger than the insertion hole 4a, and the portion with an outer diameter smaller than the insertion hole 4a (surrounding portion 5a) is inserted into the insertion hole 4a.

[0035] The fire-resistant and heat-resistant insulating material 6 has an inner diameter that is large enough to allow the stud bolt 3 to pass through, and the stud bolt 3 passes through this inner diameter portion.

[0036] The fire-resistant and heat-resistant insulating material 6 is generally circular in plan view and has a smaller outer diameter portion and a larger outer diameter portion than the insertion hole 4a, with the smaller outer diameter portion, the larger outer diameter portion, and the smaller outer diameter portion arranged in that order from the top. The smaller outer diameter portion located at the top is inserted into the insertion hole 4a. In other words, the gap between the stud bolt 3 and the insertion hole 4a is filled with the fire-resistant and heat-resistant insulating material 6.

[0037] In this embodiment, the plate material 4 is provided with a gas filling hole 7 penetrating in the vertical direction. That is, the plate material 4 has the gas filling hole 7 for filling gas. The outside (lower end) of the gas filling hole 7 is connected to one side of a hose 8, and the other side of the hose 8 is connected to a gas cylinder or the like (not shown). Gas is sent from the connected gas cylinder or the like (not shown) in the direction of the arrow shown in FIG. 1, and the gas is filled into the welding space W. Examples of the gas include a rare gas such as argon gas, and carbon dioxide gas.

[0038] In this embodiment, the plate material 4 is provided with gas suction holes 9 that penetrate vertically and suck in dust and other gases generated during welding. A heat-resistant filter 9a is provided on the welding space W side of the gas suction holes 9. This makes it possible to suck in dust, odors, and the like, preventing a nuisance to third parties, and allows the gas pressure generated by welding to escape.

[0039] <<<Welding method>>> Next, an example of a welding method for the above-described welded structure 1 will be described with reference to the drawings. Fig. 2 is an explanatory diagram for explaining the welding method, and Fig. 3 is a flowchart of the welding method.

[0040] First, as shown in FIG. 2a, the insertion holes 4a, the gas charging holes 7, the gas suction holes 9, and the blocking portions (the circled portions in dashed lines in FIG. 2a) are formed in the plate material 4 (step S1).

[0041] As described above, the insertion hole 4a has a diameter larger than the outer diameter of the stud bolt 3. In other words, this welding method has an insertion hole forming step of forming an insertion hole 4a having a diameter larger than that of the stud bolt 3, through which the stud bolt 3 is inserted, in the plate material 4. Furthermore, the method has a gas filling hole forming step of forming a gas filling hole 7 in the plate material 4 for filling with gas, and a blocking part forming step of forming a blocking part that blocks the welding space W between the steel material 2 and the plate material 4.

[0042] 2b, the ferrule 5 is provided in the insertion hole 4a of the plate material 4 (step S2). That is, this welding method includes a ferrule installation process of installing the ferrule 5 in the plate material 4. In this ferrule process, the ferrule 5 is installed in the plate material 4 by accommodating the surrounding portion 5a in the insertion hole 4a.

[0043] 2c, the plate material 4 is attached to the steel material 2 (step S3). That is, this welding method has a plate material attaching step of attaching the plate material 4 to the steel material 2 so that a welding space W is provided between the steel material 2 and the plate material 4 and the ferrule 5 is positioned within the welding space W. In the plate material attaching step, the plate material 4 is attached so that the abutting portion 5b abuts against the steel material 2.

[0044] Then, as shown in Fig. 2d, a fire-resistant and heat-resistant insulating material 6 is installed in the insertion hole 4a (step S4). That is, this welding method includes a fire-resistant and heat-resistant insulating material installation step of installing the fire-resistant and heat-resistant insulating material 6 in the insertion hole 4a.

[0045] When welding the stud bolt 3 upward (towards the ceiling) as in this embodiment, there is a risk that the fire-resistant and heat-resistant insulating material 6 will fall from the insertion hole 4a. In such a case, it is possible to prevent the fire-resistant and heat-resistant insulating material 6 from falling by, for example, fixing the fire-resistant and heat-resistant insulating material 6 or inserting the fire-resistant and heat-resistant insulating material 6 into the stud bolt 3 first and then performing a fire-resistant and heat-resistant insulating material installation step during the rod insertion step.

[0046] 1, the stud bolt 3 is inserted into the fire-resistant and heat-resistant insulating material 6, the insertion hole 4a, and the ferrule 5, and gas is sealed in the welding space W to perform stud welding (step S5). In other words, this welding method has a bar insertion process of inserting the stud bolt 3 into the insertion hole 4a and the ferrule 5, and a bar welding process of welding the tip 3a of the stud bolt 3 to the steel material 2 in a state in which the ferrule 5 is provided at the tip 3a of the stud bolt 3 and the space between the stud bolt 3 and the insertion hole 4a is filled with the fire-resistant and heat-resistant insulating material 6.

[0047] The bar welding process further includes a gas filling process of filling gas through the gas filling hole 7, and the tip 3a of the stud bolt 3 is stud-welded to the steel material 2 with the gas filled in the welding space W. In addition, in the bar welding process, the tip 3a of the stud bolt 3 is welded to the steel material 2 with the stud bolt 3 surrounded by the surrounding portion 5a.

[0048] <<<About the effectiveness of welded structure 1>>> As described above, the welded structure 1 according to this embodiment is a welded structure 1 having a steel material 2, a plate material 4 attached to the steel material 2 with a weld space W therebetween, a stud bolt 3 with a tip 3a welded to the steel material 2, and a ferrule 5 provided at the tip 3a of the stud bolt 3, and has a blocking portion that blocks the weld space W between the steel material 2 and the plate material 4, the plate material 4 has an insertion hole 4a with a diameter larger than that of the stud bolt 3 through which the stud bolt 3 is inserted, and the gap between the stud bolt 3 and the insertion hole 4a is filled with a fire-resistant and heat-resistant insulating material 6. This makes it possible to suppress the diffusion of sparks, odors, dust, etc. that are generated during welding.

[0049] Welding work is generally performed when reinforcing steel structures. However, welding work at a work site generates sparks, odors, dust, etc., which may lead to fires caused by sparks, odor problems for third parties, and health damage caused by dust.

[0050] In contrast, in the welding structure 1 of this embodiment, the welding space W is made into a closed space by the blocking portion that blocks the welding space W and the fire-resistant and heat-resistant insulating material 6 that fills the gap between the stud bolt 3 and the insertion hole 4a, and the installation of the ferrule further makes it possible to suppress the diffusion of sparks, odors, dust, and the like that are generated during welding.

[0051] In addition, in the welding structure 1 according to this embodiment, the bolts are stud-welded by the arc method. This requires a larger current to be discharged and a longer welding time than, for example, stud-welding a small-diameter bolt using the capacitor method. In other words, since sparks and the like are generated violently during welding, it can be said that this method is highly effective in suppressing the diffusion of the generated sparks and the like.

[0052] In addition, in the case of stud welding above (on the ceiling) such as stud welding the stud bolt 3 to the underside of the steel material 2 as in this embodiment, sparks and the like are more likely to spread than in the case of stud welding below (on the ground). In other words, since sparks and the like during welding are more likely to spread, it can be said that the effectiveness of suppressing the spread of sparks and the like is high.

[0053] In addition, in the welded structure 1 according to this embodiment, the ferrule 5 has a surrounding portion 5a that surrounds the stud bolt 3 and is housed in the insertion hole 4a, and a contact portion 5b that is wider in diameter than the surrounding portion 5a, is connected to the surrounding portion 5a, and abuts against the steel material 2.

[0054] As a result, because the surrounding portion 5a is accommodated in the insertion hole 4a, the position of the ferrule 5 is less likely to shift compared to when it is not accommodated, and the position of the stud bolt 3 surrounded by the ferrule 5 is also less likely to shift, so that shifting of the welding position can be suppressed.

[0055] In the welded structure 1 according to this embodiment, the stud bolt 3 is stud-welded to the steel material 2, and the plate material 4 has a gas filling hole 7 for filling with gas. This allows a rare gas or the like to be filled in the welding space W during welding, thereby suppressing deterioration in the quality of the weld.

[0056] Furthermore, the welding method for the welded structure 1 according to this embodiment includes the following steps: an insertion hole forming step of forming, in a plate material 4, an insertion hole 4a having a diameter larger than that of the stud bolt 3, through which the stud bolt 3 is inserted; a ferrule installing step of installing the ferrule 5 in the plate material 4; a plate material affixing step of affixing the plate material 4 to the steel material 2 so that a welding space W is provided between the steel material 2 and the plate material 4 and the ferrule 5 is positioned within the welding space W; a blocking portion forming step of forming a blocking portion that blocks the welding space W between the steel material 2 and the plate material 4; a fire-resistant and heat-resistant insulating material installing step of installing a fire-resistant and heat-resistant insulating material 6 in the insertion hole 4a; a bar inserting step of inserting the stud bolt 3 into the insertion hole 4a and the ferrule 5; and a bar welding step of welding the tip 3a of the stud bolt 3 to the steel material 2 in a state in which the ferrule 5 is provided at the tip 3a of the stud bolt 3 and the space between the stud bolt 3 and the insertion hole 4a is filled with the fire-resistant and heat-resistant insulating material 6.

[0057] As a result, the welding space W becomes a closed space due to the blocking portion that blocks the welding space W and the fire-resistant and heat-resistant insulating material 6 that fills the gap between the stud bolt 3 and the insertion hole 4a, and the installation of the ferrule 5 makes it possible to suppress the diffusion of sparks, odors, dust, etc. that are generated during welding.

[0058] Furthermore, in the welding method for the welded structure 1 according to this embodiment, the ferrule 5 has a surrounding portion 5a and a contact portion 5b which is wider in diameter than the surrounding portion 5a and is connected to the surrounding portion 5a. In the ferrule installation process, the surrounding portion 5a is accommodated in the insertion hole 4a to install the ferrule 5 on the plate material 4. In the plate material attachment process, the plate material 4 is attached so that the abutment portion 5b abuts against the steel material 2. In the bar welding process, the tip 3a of the stud bolt 3 is welded to the steel material 2 with the stud bolt 3 surrounded by the surrounding portion 5a.

[0059] As a result, because the surrounding portion 5a is accommodated in the insertion hole 4a, the position of the ferrule 5 is less likely to shift compared to when it is not accommodated, and the position of the stud bolt 3 surrounded by the ferrule 5 is also less likely to shift, so that shifting of the welding position can be suppressed.

[0060] In addition, the welding method for the welded structure 1 according to this embodiment further includes a gas filling hole forming process for forming a gas filling hole 7 in the plate material 4 for filling the gas, and a gas filling process for filling the gas through the gas filling hole 7. In the bar welding process, with gas filled in the welding space W, the tip 3a of the stud bolt 3 is stud welded to the steel material 2.

[0061] This allows a rare gas or the like to be sealed in the welding space W during welding, thereby making it possible to suppress deterioration in the quality of the welding.

[0062] <<<About modified versions>>> Next, an example of a modified example of this embodiment will be described. Fig. 4 is a schematic cross-sectional view of a modified welded structure 10. As shown in Fig. 4, in the modified welded structure 10, a fireproof material 11 and a plate material 12 are used instead of the plate material 4. Furthermore, a ferrule 5 is used instead of the fireproof and heat-resistant insulating material 6.

[0063] In the welded structure 10, the plate material 12 is not concave but flat, and the fireproof material 11 is used in the portion that was the protruding portion (blocking portion) in the plate material 4. In other words, the fireproof material 11 is a blocking portion, and is provided on the entire outer periphery of the plate material 12, and blocks the weld space W between the steel material 2 and the plate material 12. Note that an example of the fireproof material 11 is Fi-Block (registered trademark) made by Sekisui Chemical Co., Ltd., and the blocking portion can be formed, for example, in the plate material attachment process described above.

[0064] Furthermore, two ferrules 5 are used in the welded structure 10. One is used in the same manner as in this embodiment, and the other has a surrounding portion 5a accommodated (filled) in the gap between the plate material 12 and the stud bolt 3 as a substitute for the fire-resistant and heat-resistant insulating material 6 on the underside of the plate material 12. In other words, since the ferrule 5 is a fire-resistant, heat-resistant, insulating material, it is used in the modified example as a substitute for the fire-resistant and heat-resistant insulating material 6. In addition, a method of filling the gap between the plate material 12 and the stud bolt 3 using fire-resistant putty or the like as a substitute for the fire-resistant and heat-resistant insulating material 6 can also be used.

[0065] ===Other embodiments=== The above-mentioned embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

[0066] In addition, in the above embodiment, the plate material 4 has a substantially rectangular shape in a plan view, but this is not limited thereto, and may have, for example, a substantially circular shape.

[0067] In the above embodiment, the welding is performed by sealing a rare gas or the like in the welding space W, but the present invention is not limited to this, and the rare gas or the like does not need to be sealed in. In this case, the gas sealing hole 7 and the hose 8 are not necessary and therefore do not need to be provided. [Explanation of symbols]

[0068] 1 Welded structure, 2 Steel material, 3 Stud bolt (bar material), 3a Tip, 4 Plate material, 4a insertion hole, 5 ferrule, 5a surrounding portion, 5b abutment portion, 6 fire-resistant and heat-resistant insulating material, 7 gas filling hole, 8 hose, 9 gas suction hole, 9a heat resistant filter, 10 welded structure, 11 fireproof material (blocking portion), 12 plate material, W welded space,

Claims

1. Steel and A plate material is attached to the steel material with a welding space therebetween; A bar material having a tip welded to the steel material; a ferrule provided at the tip portion of the bar; A welded structure having a closing portion that closes the welding space between the steel material and the plate material, the plate material has an insertion hole having a diameter larger than that of the bar material, through which the bar material is inserted; A gap between the rod and the insertion hole is filled with a fire-resistant and heat-resistant insulating material, the fire-resistant and heat-resistant insulating material has an outer diameter portion smaller than the insertion hole, and an outer diameter portion connected to the smaller outer diameter portion and larger than the insertion hole, A welded structure, characterized in that the small outer diameter portion is inserted into the insertion hole and the large outer diameter portion abuts against the plate material.

2. 2. The welded structure according to claim 1, The ferrule is a surrounding portion that surrounds the bar and is accommodated in the insertion hole; a contact portion having a diameter larger than that of the surrounding portion, connected to the surrounding portion, and contacting the steel material; A welded structure comprising:

3. The welded structure according to claim 1 or 2, The bar is stud welded to the steel material; A welded structure characterized in that the plate material has a gas filling hole for filling a gas therein.

4. a through-hole forming step of forming an insertion hole in a plate material, the through-hole having a diameter larger than that of the bar material and through which the bar material is inserted; a ferrule installation step of installing a ferrule on the plate material; a plate material attachment process of attaching the plate material to the steel material such that a welding space is provided between the steel material and the plate material and a ferrule is positioned within the welding space; a closing portion forming process for forming a closing portion that closes the welding space between the steel material and the plate material; a fire-resistant and heat-resistant insulating material installation step of installing a fire-resistant and heat-resistant insulating material in the insertion hole; a rod inserting step of inserting the rod into the insertion hole and the ferrule; a bar welding process for welding the tip of the bar to the steel material in a state in which the ferrule is provided at the tip of the bar and the space between the bar and the insertion hole is filled with the fire-resistant and heat-resistant insulating material; having the fire-resistant and heat-resistant insulating material has an outer diameter portion smaller than the insertion hole, and an outer diameter portion connected to the smaller outer diameter portion and larger than the insertion hole, A welding method, characterized in that the small outer diameter portion is inserted into the insertion hole and the large outer diameter portion is in contact with the plate material.

5. The welding method according to claim 4, The ferrule includes a surrounding portion and a contact portion having a larger diameter than the surrounding portion and connected to the surrounding portion, In the ferrule installation step, the surrounding portion is received in the insertion hole, thereby installing the ferrule on the plate material, In the plate material attachment step, the plate material is attached so that the abutment portion abuts against the steel material, The welding method is characterized in that, in the bar welding step, the tip of the bar is welded to the steel material in a state in which the surrounding portion surrounds the bar.

6. The welding method according to claim 4 or 5, The method further includes a gas filling hole forming step of forming a gas filling hole in the plate material for filling a gas, and a gas filling step of filling a gas through the gas filling hole, The welding method is characterized in that, in the bar welding step, the tip of the bar is stud-welded to the steel material with gas sealed in the welding space.

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