JPH01181971A - Enclosed arc welding method - Google Patents

Abstract

PURPOSE:To increase efficiency of field work and to reduce the welding cost by abutting a strap material surrounding a part of groove space on the side of lower material to be welded by providing a gap with upper material to be welded and building up weld metal from the lower material to be welded in the vicinity of the strap material to form a bridge part. CONSTITUTION:The groove space 15 is provided between the upper and lower reinforcing bars 11 and 12 and the strap material 13 is abutted on the side peripheral surface of the lower reinforcing bar 12. A part of the groove space 15 is surrounded by the strap material 13 and the gap is provided between the upper part of the strap material 13 and the upper reinforcing bar 11. An electrode 18 is inserted into the groove space 15 to start welding from the vicinity of the strap material 13. Molten metal 20 is built up by utilizing the strap material 13 and the upper reinforcing bar 11 and the lower reinforcing bar 12 are bridged. By this method, the efficiency of work at a construction field can be extremely increased and welding can be performed at the low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an enclosed arc welding method for enclose welding rod-shaped materials to be welded, such as reinforcing bars, in a vertically erected state.

[Prior art] The conventional enclosed arc welding method for vertical joints was carried out by machining a so-called diagonal groove (Japanese Patent Publication No. 52
-35624). FIG. 4 is a side view showing the conventional enclosed arc welding method for a vertical joint, and FIG. 5 is a cross-sectional view taken along line V-■. In this method, for example, irregularly shaped reinforcing bars 1 are provided with their joint surfaces inclined with respect to the axial direction, two reinforcing bars 1 are arranged one above the other with a predetermined groove space between them, A pair of split copper pads 2 are arranged to surround this groove space. Then, the welding rod 3 is inserted into the groove space through the welding port 4 of the copper dowel 2 provided above the groove space, and weld metal is filled from the bottom to the top of the groove space. Thereby, the materials to be welded in a fixed vertical position can be quickly and soundly joined.

In recent years, the method of joining reinforcing bars embedded in the concrete columns of reinforced concrete buildings has been to use the pre-assembly method, which aims to improve the efficiency of the method of joining reinforcing bars one by one at the construction site. are becoming more common. In other words, multiple reinforcing bars are placed two-dimensionally within the cross-sectional area of a column in a factory or on the ground, stacked on top of each other on a construction site, and the stacked assemblies are welded together in a vertical position. The Ikusaki construction method is used for large-scale reinforced concrete buildings.

The above-mentioned enclosed arc welding method has the advantage that the shape of the joined joint does not become excessively large, and it is easy to construct hoop bars in the subsequent process. It is used.

[Problems to be solved by the invention] However, the conventional enclosed arc welding method
Since the welding groove shape is a diagonal shape, it has the following drawbacks. In other words, in the case of this obliquely shaped groove, there is a restriction that welding must be performed by inserting a welding rod into the groove from above in the extending direction of the groove surface. For this reason, in the pre-assembled reinforcing bar method, it is necessary to take into account the welding direction in advance and pre-assemble the reinforcing bars so that the grooves are in that direction. It is necessary to take into consideration the direction of welding work and process so that the inclined joint surfaces are parallel to each other.

For this reason, it is necessary to strictly control the direction of reinforcing bars during pre-assembly, and although the pre-assembly method is adopted for the purpose of speed and efficiency, in practice the work is extremely complicated and inefficient. There is a problem that.

In addition, machining the joint surfaces of reinforcing bars at an angle with respect to their axis is a complicated process and requires a large amount of cutting.
There is a problem that the yield decreases. Furthermore, when this beveling is performed on-site by gas cutting, there is a drawback that gas notches are likely to occur and much labor is consumed in grinding the beveling surface (joint surface) with a grinder.

The present invention has been made in view of such problems, and includes:
To provide an enclosed arc welding method in which the joint surface of the groove can be easily processed, the groove processing time can be shortened, and there are no restrictions on pre-assembly, and the pre-assembly can be performed quickly and easily. purpose.

[Means for Solving the Problems] The enclosed arc welding method according to the present invention includes a pair of rod-shaped materials to be welded, the joint surfaces of which are substantially perpendicular to the axial direction, and a pair of materials to be welded between the joint surfaces. A predetermined gap is provided between the materials, which are arranged vertically with a predetermined groove space and are in contact with the side surface of the lower workpiece to surround a part of the groove space, and the upper workpiece. First, a bridge portion is formed by applying molten metal from the side of the material to be welded below in the vicinity of the material.

Note that the joining surface being substantially perpendicular to the axial direction of the rod-shaped material to be welded means that when performing welding by the method of the present invention,
This means that the installation of this material does not have an inclination that would limit the position and insertion position of the hot material, etc. In other words, there is no problem in construction without considering the direction of welding. The slope of is included.

In addition, to form a bridge by applying molten metal from the lower workpiece side means to apply molten metal from below to the entire or more than half of the bridge, and to form this bridge. During the process, a small amount of molten metal may be applied to the upper side of the welded material, or molten metal may be applied to confirm the occurrence of an arc.

Furthermore, when this material is stacked on the side surface of the welded material below, it is not necessary for the material to be in contact with the welded material over the entire area of the overlapping area, but only in a part of the area. That's fine. Moreover, it goes without saying that the material does not need to contact the entire side surface of the material to be welded below.

[Function] In the present invention, a horizontal groove is provided, and the material is disposed in contact with the side surface of the lower member to be welded.

This material surrounds a part of the groove space and is disposed with a predetermined gap between it and the material to be welded above.

Then, a bridge portion is formed by applying weld metal from the lower welded material side in the vicinity of the material. In this case, since the material is disposed on the back side of the groove, the ends of the joint surfaces of the materials to be welded will not be welded together at the start of welding. Further, by using this material, a bridge portion can be easily provided between the joint surfaces of the upper and lower welded materials. Furthermore, since the slag floats upward and is discharged from the gap formed between the material and the material to be welded above, no slag remains in the weld between the joint surfaces.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings. FIGS. 1(a) to 1(e) are schematic diagrams showing the enclosed arc welding method according to the embodiment of the present invention in the order of steps;
FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1(a).

The joint surfaces of the upper reinforcing bars 11 and the lower reinforcing bars 12 are substantially perpendicular to the axial direction, so that the reinforcing bars 11.
12 are arranged vertically with their axes aligned, the two joint surfaces face each other substantially horizontally and in parallel. The copper dowel 14 has a U-shaped horizontal cross section, and the reinforcing bars 11.1 are centered around the groove space 15 formed between the main reinforcing bars 11 and the lower reinforcing bars 12.
It is arranged so as to embrace 2. Both reinforcing bars 11 and 12 are held by a pair of clampers (not shown) fixed to a copper butt 14 so that their axes coincide with each other at their opposite ends. 14 and a clamper, they are arranged to face each other vertically.

A recess 16 is formed in the copper dowel 14 behind the groove space 15 between the reinforcing bars 11 and 12, and the copper dowel 13 is inserted into the reinforcing bar 1 below.
It is disposed in the recess 16 in contact with the side circumferential surface of the back side of 2. This support member 13 is fixed by being pressed against the lower reinforcing bar 12 from behind by a bolt 17 passing through the copper support member 14 in the horizontal direction.

After arranging the main reinforcing bar 11, the lower reinforcing bar 12, the support material 13, and the copper dot 14 in this way, as shown in FIG. Bevel space 1
5, and the inner side of the groove space 15 near the material 13)
Start welding.

That is, first, the material 13 at the joint surface of the lower reinforcing bar 12
Start the arc at a position of 5 to 6 dragons in front of , immediately move the arc to a part of the corner between the joint surface of the lower reinforcing bar 12 and the material 13, and perform semi-weaving while shortening the arc, Wait for the molten metal to rise.

Then, as shown in FIG. 1(b), the molten metal 20 is piled up on the joint surface of the lower reinforcing bar 12 using the material 13. In this case, the generated slag 21 floats on the molten metal 20. And the joint surface of the upper reinforcing bar 11 (upper groove)
When the distance between the molten metal 2o and the molten metal 2o becomes 2 to 3 mm, semi-weaving is stopped, the arc is stopped, and the corner at the end of the earthen floor is melted and bridged.

After the main reinforcing bars 11 and the lower reinforcing bars 12 are bridged, as shown in Fig. 1 (c
), while performing semi-weaving, the welding rod 18 is directed upward and downward alternately while discharging the generated slag out of the groove using the gap between the upper reinforcing bar 11 and the material 13. to secure weld penetration on the dirt floor end side and Shimonoseki end side.

In this way, the molten metal 20 is continued to be stacked up to the frontmost part of the groove, as shown in FIGS. 1(d) and 1(e).

Next, the arc is stopped, the molten metal 20 is cooled and solidified, and then the clamper is removed to complete the welding.

In the method of this embodiment, by bringing a small piece of abutting material 13 into contact with the lower reinforcing bar 12 in the inner part of the copper abutment 14, it is possible to bridge the weld metal 20 between the main reinforcing bar 11 and the lower reinforcing bar 12. do. Then, the ■-shaped groove formed at the joint surface of the main reinforcing bar 11 and the lower reinforcing bar 12 is vertically arc welded. If welding is performed without using this material 13, the main reinforcing bar 1 will be
An appropriate bridge between 1 and the lower reinforcing bar 12 is not formed. This is because, due to the welding posture, the molten metal 20 only spreads over the groove surface (joint surface) of the lower reinforcing bar 12 and is difficult to reach the main reinforcing bar 11. In this way, the small piece of material 13 has the function of depositing molten metal 20 in the deep part of the groove and promoting bridging between the upper and lower reinforcing bars.

In order to obtain such an effect, it is necessary that the central angle θ between both ends of the lower reinforcing bar 12 in the circumferential direction of the member 13 and the axis of the reinforcing bar 12 is 30° or more. However, if the material is too large, it will be difficult to discharge the slag 21 outside the groove during enclosed arc welding, and large-scale slag entrainment and resulting welding defects such as poor fusion will likely occur. Become. Therefore, the material 13 is approximately (150/36
0) Limit the amount to cover an area of size 6 or less.

In addition, the distance d (mu) between the upper reinforcing bar 11 and this material 13 is 2
It is preferable to set it to D/2 mm. However, D
(mu) is the distance between the upper reinforcing bar 11 and the lower reinforcing bar 12. If d is less than 2 dragons, the escape of the slag 21 will be poor, and slag entrainment will likely occur.

Also, discharging the slag 21 requires a high degree of skill and strict monitoring of welding conditions. On the other hand, when d exceeds D/2, it is difficult for the molten metal 20 to form a bridge. For this reason, the joint is not completed.

In addition, during welding work, the inner circumferential surface of the material 13 and the outer circumferential surface of the reinforcing bar 12 are curved with the same curvature, and the material 13 is in full contact with the reinforcing bar work 2 within the range of the above-mentioned center angle θ. It is ideal to do so. However, as shown in FIG. 3(a), the diameter of the lower reinforcing bar 2 is large, and the central part of the material 13 and the reinforcing bar 1
In the case where a gap a is formed between the lower reinforcing bar 12 and the lower reinforcing bar 12, as shown in FIG.
Both ends of the reinforcing bar 12 may be separated from the circumferential surface of the reinforcing bar 12 by a distance b. In this case as well, a is about 2 or less, and b is 2 to 3
mm, the same effect as when the entire surface of the material 13 is in contact with the lower reinforcing bar 12 can be obtained.

As a result, a dedicated material 13 is used for each reinforcing bar with a different cross-sectional diameter.
It is possible to avoid the complexity of preparing .

Next, the results of actually performing vertical welding of the (1) groove using the method of the embodiment of the present invention will be described.

Reinforcing bars used: 5D35, 5D40 (JIS) Reinforcing bar shape: JIS G3112 (steel bars for reinforced concrete) Reinforcing bar diameter: 22 for D21, 38 for D38
mm Welding rod, for 5D35, use JISD5816 For 5D40, use JISD7016 Groove spacing: 10 rhymes and 14 dragons for D22, 12 mm and 16 mm for D38 Our material: width is 25 mm, length 5M41 material (JIS) with a thickness of 20 mm and a thickness of 10 mm Welding current: 150 to 170 A for D38, D22
In the case of 120 to 130A, the characteristics of the welded part obtained when welding under these welding conditions are shown in Table 1 below.

Both have sufficient strength and ductility.

In addition, Table 2 below shows welding results when D41 reinforcing bars with a diameter of 41 mm were welded using the method of the embodiment of the present invention and when welding was performed using the conventional method. .

Table 2 As is clear from Table 2, according to the method of this embodiment, the time required was approximately halved compared to the conventional method, resulting in extremely high efficiency.

In addition, as mentioned above, since enclosed arc welding can be performed with the joint surfaces horizontal, when pre-assembling reinforcing bars,
There is no need to assemble reinforcing bars taking their direction into consideration, and therefore pre-assembling can be done quickly and the advantages of the pre-assembling method can be fully utilized. Further, since it is sufficient to form a joint surface substantially perpendicular to the axial direction of the reinforcing bar, it is easy to form a groove shape, and the yield is high because there are few cut-off parts.

[Effects of the Invention] According to the present invention, the groove shape is a square square perpendicular to the axial direction of the material to be welded, and there is an advantage that there is no restriction in directionality with respect to the reinforcing bar axis to be installed. In addition, since the groove is perpendicular to the reinforcing bar axis, the reinforcing bar can be used as it is, or as it is after high-speed cutting or gas cutting, and processing is simple.

Furthermore, there is no need to remove slag until the welding is completed, and the groove area is reduced to 70% of the conventional method, so welding can be performed with even higher efficiency.

Furthermore, there is no need to pull the reinforcing bars to be joined together, making it possible to join constrained reinforcing bars.

As a result, according to the present invention, work at a construction site can be performed extremely efficiently, and welding can be performed at low cost.

[Brief explanation of the drawing]

1(a) to 1(e) are schematic diagrams showing the process order of the enclosed arc welding method according to the embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ of FIG. Figure 3(a),
(b) is a plan sectional view of the reinforcing bar, FIG. 4 is a side view showing the conventional method, and FIG. 5 is a sectional view taken along the line V-■ in FIG. 4. 11.12; Reinforcing bar, 13; Material, 14; Copper metal, 15:
Bevel space

Claims (3)

[Claims] (1) A pair of rod-shaped materials to be welded, the joint surfaces of which are substantially perpendicular to the axial direction, are arranged one above the other with a predetermined groove space between the joint surfaces, and the materials to be welded below This material is placed in contact with the side surface of the material and surrounds a part of the groove space, with a predetermined gap provided between it and the material to be welded above, and first, the material to be welded below is An enclosed arc welding method characterized by forming a bridge by piling up molten metal from the welding material side. (2) The gap between the material and the material to be welded above is 2 mm.
2. The enclosed arc welding method according to claim 1, wherein the distance is equal to or less than 1/2 of the distance between the joint surfaces of the upper and lower welded materials. (3) The enclosed arc welding according to claim 1 or 2, wherein the material is in contact with the axis of the lower workpiece in a region forming a central angle of 30 to 150 degrees. Method.