JPH01186276A - Enclosed arc welding method - Google Patents

Abstract

PURPOSE:To increase efficiency of work by inserting a welding means into groove space formed by a couple of bar-shaped materials to be welded whose joining surface is vertical to the axial direction and a strap material fixed by using a copper strap to a perform arc welding. CONSTITUTION:The couple of bar-shaped materials 11 and 12 to be welded whose joining surface is vertical to the axial direction are arranged upward and downward by providing a prescribed groove at joining surface space 15. The copper strap 14 is provided so as to cover a part of the joining surface of the upper and lower materials 11 and 12 to be welded. The strap material 13 having strength same as or below that of the materials 11 and 12 to be welded is arranged in contact with the materials to be welded and said strap material 13 is pressed and fixed thereon by a pressing jig 17 arranged to the copper strap 14. The welding means is inserted into the groove space 15 formed hereby to perform arc welding. By this method, the efficiency of work is increased and reliability of joint strength is improved.

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 performed by machining a so-called diagonal I-shaped groove (Japanese Patent Publication No. 52
35624), FIG. 6 is a side view showing a conventional enclosed arc welding method for a vertical joint, and FIG. 7 is a cross-sectional view taken along the line ■-■. 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 from the welding port 4 of the copper dowel 2 provided on the upper side of the groove space, and the 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. 9 In other words, the pre-assembly method involves pre-assembling multiple reinforcing bars in a factory or on the ground, stacking them on top of each other at the construction site, and welding the stacked assemblies together in a horizontal position. It is used in 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 reinforcements 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 oblique, 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 unworkable. There is a problem with efficiency.

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 rate decreases. Furthermore, when this beveling is performed on-site by gas cutting, there is a disadvantage that gas notches are likely to occur and much labor is consumed in grinding the beveling surface (the joint surface).

The present invention was 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. The materials are arranged one above the other with a predetermined groove space provided, and the materials surrounding a part of the groove space are brought into contact with the side surfaces of the welding material below, and a predetermined gap is provided between the material and the material to be welded above. and covering a part of the joint including the groove space and the joint surfaces of the upper and lower parts to be welded with a copper butt having an opening on the side where the material is not arranged, A welding means is inserted into the groove space from the opening side and arc welding is performed between the joint surfaces.

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, when this material is overlapped with the side surface of the welded material below, it is not necessary for the material to contact 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.

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

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.

Further, a part of the joint including the groove space and the joint surfaces of the upper and lower workpieces to be welded is covered with a copper dowel having an opening on the side where the workpiece is not disposed.

After arranging the material and the copper dowel in this manner, a welding means such as a welding rod is inserted into the groove space through the opening, and arc welding is performed between the joint surfaces. First, for example, a bridge portion is formed by pouring molten metal from the lower welding material side in the vicinity of the material.

In this case, since the material is disposed on the deep side of the groove space, the end portion of the joint surface of the material to be welded does not burn through 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. Furthermore,
Since the sides of the material to be welded except for the opening are covered with a copper dowel, the molten metal will not burn through even if a high current is applied during the welding period and welded at high speed. Moreover, the appearance of the welded part after welding is finished beautifully.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side cross-sectional view showing the enclosed arc welding method according to the embodiment of the present invention, FIG. 3(a) to 3(e) are also schematic diagrams showing the operation.

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 made of copper or a copper alloy has a cross-shaped horizontal cross section, and is a joint that includes the joint surfaces of the reinforcing bars 11° and 12 around the groove space 15 formed between the upper reinforcing bars 11 and the lower reinforcing bars 12. It is arranged so as to embrace the parts. This copper butt 14 has a slight gap between its inner peripheral surface and the joint peripheral surface of the reinforcing bars 11 and 12.

A reinforcing bar 11.1 is attached to one tip of the copper dowel 14.
In order to provide a predetermined groove interval between the two joint surfaces, a scale 22 is cut out with the same length as the groove interval.

Clampers 30 are provided on the upper and lower end surfaces of the copper butt 14, respectively.
is fixed. This clamper 30 has half-shaped clamp members 31 and 32 each having a semicircular notch, which are connected at their base ends so as to be mutually rotatable around a vertical axis, and one clamp member 31 has a copper stopper. It is fixed at 14.

When the clamping members 31, 32 are brought together and integrated, the notches form a circular hole having a diameter approximately equal to that of the reinforcing bar 11, 12. The insert pin 34 is attached to the tip of the clamp member 31 so as to be rotatable around a vertical axis.
A handle 33 is screwed into the handle 4.

On the other hand, a recess into which an insert pin 34 can be engaged is formed at the tip of the clamp member 32.

In the clamper 30 configured in this way, first,
Reinforcement bar 11 (or 12) is inserted into the semicircular notch of clamp member 31.
is fitted, the clamp member 32 is rotated to match the clamp member 31, and both clamp members 31 and 32 surround the reinforcing bar 11 (or 12). Then, the insert pin 34 is rotated to engage the distal end recess of the clamp member 32, and the handle 33 is rotated to advance the handle 33 toward the distal end of the clamp member 31. The distal end of the clamp member 32 is clamped and tightened between the distal end of the clamp member 32 and the distal end of the clamp member 32. As a result, both reinforcing bars 11 and 12 are gripped by a pair of clampers 3o so that their axes coincide at their opposing ends, and are vertically opposed to each other via the copper butt 14 and clamper 30. It will be arranged as follows. In addition, reinforcing bar 11.1
The groove interval between the two joint surfaces may be adjusted by referring to the scale 22 provided at the tip of the copper dowel 14.

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 material 13 is fixed by being pressed against the lower reinforcing bar 12 from behind by a bolt 17 passing horizontally through the copper material 14. If the material 13 is made of metal, it is attached to the welded part after welding is completed. It is joined and becomes part of the joint. on the other hand,
When a refractory material is used as the material 13, an underwave bead is formed to improve the appearance, and since the material 13 is removed after construction, the appearance of the welded part can be observed to determine joint performance.

After arranging the upper 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, near the material 13 (on the back side of the groove space 15)
Start welding from.

That is, first, the material 13 at the joint surface of the lower reinforcing bar 12
The arc is started at a position 5 to 6 mm in front of the steel, and the arc is immediately moved to a part of the corner between the joint surface of the lower reinforcing bar 12 and the material 13, and while the arc is shortened, weaving is performed and melting is performed. Wait for the 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 section)
When the distance between the weaving and the molten metal 20 becomes 2 to 31 am, the weaving is stopped, the arc is made to stand still, and the corners of the upper joints are melted and bridged.

After the upper reinforcing bar 11 and the lower reinforcing bar 12 are bridged, as shown in Fig. 1 (C
), while performing 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. Ensure weld penetration on the lower section side and the lower section side. In this way, as shown in FIG. 1(d) and FIG. 1(e), the molten metal 20 is continued to be stacked up to the frontmost part of the groove.

In addition, at the forefront part (finishing side end part) of the lower reinforcing bar 12, it is preferable to repeatedly interrupt and form an arc to cool the weld metal and build it up.

When welding continuously, so-called overlap occurs in the lower reinforcing bar 2, and undercuts tend to occur in the upper reinforcing bar 11.

Next, the arc is stopped, and after the molten metal 20 is cooled and solidified, the clamper 30 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 upper reinforcing bar 11 and the lower reinforcing bar 12. do. Then, the I-shaped groove formed at the joint surface of the upper reinforcing bar 11 and the lower reinforcing bar 12 is vertically arc welded. When welding without using this material 13, the upper reinforcing bar 1
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 upper 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.

Further, in this embodiment, as described above, the groove space 15
In addition to the backing material 13 being placed on the back side of the groove, the sides of the groove space are covered with a copper backing 14.

Therefore, melting of the molten metal 20 is reliably prevented.
The welding current can be kept high throughout the welding period to allow high speed welding. If the copper dowel 14 is not used, when welding the peripheral edge of the joint surface of the reinforcing bars 11, 12, it is necessary to reduce the current to prevent burn-through. In this way, by using the copper dowel 14, welding work becomes easier.

Furthermore, the copper of the copper dowel 14 or the copper dot has a property of not getting wet with the molten metal 20, and there is a slight gap between the inner circumferential surface of the copper dot 14 and the groove space 15. A welded part formed by forming an underwave bead in this gap and surrounded by the copper dowel 14 has a beautiful appearance.

In this welding process, as shown by the arrow 22 in FIG. 4, the arc is swung horizontally to perform weaving. In other words, first start weaving from the fillet between the joint surface of the material 13 and the lower reinforcing bar 12, and move the beam to the finished end (the frontmost part of the groove) on the near side while swinging an arc in the left and right direction. move it.

By performing such weaving to build up molten metal on the joint surface, the joint surface is maintained at a uniformly high temperature, slag is prevented from being drawn in, and the work of removing slag becomes unnecessary. Therefore, it is possible to carry out welding work substantially continuously.

If the arc is cut in the middle without continuous weaving, it will be necessary to remove the slag. During slag removal work, when the welded part is cooled to near room temperature, 200
It is necessary to heat it up to above °C and restart welding.

Note that at the initial stage of the welding process, the arc is swung from side to side, but at the middle stage, it is preferable to sway the arc from side to side and also add weaving with a small amplitude in the vertical direction. This makes it easier to create a bridge, and also makes it easier for slag to be discharged through the gap between the material 13 and the main reinforcing bar 11, thereby reliably preventing slag from getting caught up.

In addition, by performing weaving, it is possible to form a proper so-called wavy bead on the side surface of the joint, and it is also necessary to take special measures to prevent molten metal from burning through the finished end of the front side. It disappears.

As mentioned above, in order to form a bridge using the material 13, the central angle θ between the circumferential ends of the lower reinforcing bar 12 in the material 13 and the axis of the reinforcing bar 12 is 30 degrees or more. It is necessary. 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 has a central angle θ of the reinforcing bar 11°12 to be welded.
The area should be limited to an area no larger than approximately (150/360)' of the outer circumference of the area.

In addition, the distance d(+u) between the main reinforcing bar 11 and this material 13 is 2
It is preferable to set it to D/2 am. However, D
(mm) is the distance between the main reinforcing bars 11 and the lower reinforcing bars 12. If d is less than 211!1, the escape of the slag 21 will be poor, and slag entrainment will likely occur.

Further, in order to discharge the slag 21, a high level of skill and strict monitoring of welding conditions are required. 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 12 within the range of the above-mentioned center angle θ. That is ideal. However, as shown in FIG. 5 (a), the diameter of the lower reinforcing bar 12 is large, and the central part of the material 13
As shown in FIG. 5(b), when the diameter of the lower reinforcing bar 12 is small,
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, if a is approximately 2 mm or less and b is 2 to 3 ml+, 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 the

Moreover, it is preferable that the groove interval defined by the joint surfaces of the upper and lower reinforcing bars 11.12 is set according to the diameter of the reinforcing bars 11.12. If the gap between the grooves is too narrow, it will be difficult to operate the rod, leading to poor penetration and slag entrainment. Therefore, loosen the clamper 30 and separate the reinforcing bars 11 and 12, or loosen the joint surface of the reinforcing bars. By reprocessing, the groove space is made appropriate. On the other hand, if the groove spacing is too wide, it is uneconomical because the consumption of welding rods increases and the welding time increases.

In order to maintain this groove spacing appropriately, as described above, a notch or the like may be formed in the copper dowel 14 to provide a scale 22, and this scale 22 may be used to adjust the groove spacing.

This streamlines the work. However, the groove spacing can also be adjusted by using a standard spacing gauge and inserting this standard spacing gauge between the joint surfaces.

If the eccentricity between the reinforcing bars 11, 12 is too large, it will be difficult to install the jig and will cause undercuts and overlaps. Therefore, the eccentricity of the reinforcing bar is 11.12
If the diameter exceeds 1/10 of the nominal diameter, it is preferable to install a welding jig using a reinforcing bar clamp adjuster or the like.

On the other hand, if the reinforcing bars to be joined are mutually restrained, appropriate corrective measures such as a bender are taken to keep the deviation between the joining surfaces within a predetermined range.

Incidentally, it is preferable to remove deposits that adversely affect welding, such as oil, paint, concrete mist, severe rust, etc. on the groove part, by using a wire brush or grinding.

In addition, depending on the purpose of construction, welding can be performed using a welding method other than a coated arc welding rod. By using electrode wire melting characteristics, it is possible to carry out welding in about 1/2 to 1/3 of the welding time of covered arc welding. However, it is of course necessary to provide a suitable windproof means to create a complete shielding condition.

In addition, the shape of the material 13 is as in the above embodiment, the shape of the reinforcing bar 11
．． The contact surface to 12 is curved and has a recess, and the back surface thereof is not limited to a flat surface. For example, it may be curved with a constant thickness, like cutting out a part of a cylinder.

Next, the results of actually performing vertical welding of a work groove using the embodiment method of the present invention will be described.

Reinforcing bars used: 5D35, 5D40 (J Is) Reinforcing bar shape: JIS G3112 (steel bars for reinforced concrete) Reinforcing bar diameter: D21 and D38 Welding rod: For 5D35, use JISD5816 For 5D40, use JISD7016 Groove spacing: D22 In the case of 10 dragon and 14mm, D38
In the case of 12mm and 16mm, the width is 25+u, the length is 20++n, and the thickness is 1
0Ryu 5M41 material (JIS) Welding current: 150 to 170A 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.

Further, Table 2 below compares the welding results when reinforcing bars with a diameter of D41 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 perpendicular to the axial direction of the welded material, and there is an advantage that there is no directional restriction with respect to the axis of the welded material to be constructed. . Further, since the groove is perpendicular to the axis of the material to be welded, the reinforcing bar can be used as it is, for example, or as it has been cut at high speed or gas cut, and processing is simple.

Furthermore, it is not necessary 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, since the side portions of the material to be welded are covered with the copper dowel, burn-through of molten metal can be reliably prevented, and high-speed welding with high current is possible.
Also, the appearance of the welded part becomes beautiful.

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]

FIG. 1 is a side view showing an enclosed arc welding method according to an embodiment of the present invention, FIG. ) to (e) are schematic diagrams showing this enclosed arc welding method in the order of steps, FIG. 4 is a schematic diagram showing the weaving method,
Figure 5(a). 6(b) is a plan sectional view of the reinforcing bar, FIG. 6 is a side view showing the conventional method, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6. 11.12; Rebar, 13; Material, 14; Copper metal, 15;
Bevel space, 30; clamp

Claims (3)

[Claims] (1) A pair of rod-shaped materials to be welded whose joint surfaces are substantially perpendicular to the axial direction are arranged one above the other with a predetermined groove space between the joint surfaces, and the groove space is The material that surrounds a part of the groove space is brought into contact with the side surface of the lower workpiece and is arranged with a predetermined gap between the upper workpiece and the groove space and the upper and lower workpieces. A part of the joint, including the joint surface of An enclosed arc welding method characterized by arc welding between joint surfaces. (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.