JPS624906A - Pipe for welded joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the two ends of a pipe when welding and connecting reinforcing bars.
By simply fitting real reinforcing bars, the reinforcing bars can be faced with a defined groove gap, and the molten metal during welding can be prevented from dripping, ensuring that molten metal is poured into the groove gap. This invention relates to a pipe for a welded joint that can be filled to form a welded joint with high strength and reliability.

[Conventional technology]

Conventionally, as shown in Fig. 10, four through holes (2) (
Connecting pipe (1) with 2a) (2b) (2c) opened
It has been proposed to weld and connect reinforcing bars (5) and (5) using (Utility Model Application No. 16523/1983).

The pipe (1) is made by abutting two reinforcing bars (5) (5) inserted at both ends of the pipe at the center of the pipe, welding the reinforcing bars (5) (5) to both ends of the pipe, and then making each through hole. (2
) Hole (2) as shown in Figure 11 while welding the hole edge and reinforcing bar.
It is used by filling it with weld metal (6).

However, in the case of welded joints using the above pipes, the through holes (
2) to (2c) are opened at equal intervals in the circumferential direction of the joint, so the width of the connection part (10) between the through holes becomes small, and when welding the hole edges, the connection part (10) becomes red hot, changes the metallographic structure, and gradually reduces the strength of the pipe itself.

Furthermore, if a groove gap is provided between the reinforcing bars (2) (2), when welding the upper through hole (2a), molten metal will fall from the lower through hole (2b), so the reinforcing bars (2) (2) The end faces of the welding wire must be brought into contact with each other, and the end faces cannot be welded together with the welding wire to form a strong bond.

Due to the above points, the strength of the welded joint was low, and the pipe was never actually constructed using this pipe.

Therefore, the applicant previously proposed a pipe (1
), we proposed a pipe for welded joints with only one welding through hole (2) approximately in the center of the pipe.
9305).

As shown in Fig. 7, reinforcing bars (5) (
5') facing each other, insert a welding wire into the groove gap from the through hole (2), fill the groove with molten metal sequentially from the back by carbon dioxide shield welding, and then fill the through hole (2) with molten metal as well. Fill it in.

This is because the through hole (2) for welding is created at only one location on the circumference of the pipe (1), so the hole only needs to be filled in one location, so the side opposite to the hole is not affected by heat, which reduces the strength of the pipe itself. In addition to preventing deterioration, welding work time can be significantly shortened.
However, the welded metal was present between the groove gap W between both reinforcing bars, and a welded joint with high strength and reliability was realized.

[Problem to be solved]

However, even with the pipe shown in Figure 6, which has many advantages, if welding is carried out with the reinforcing bars (5) (5) in contact with the end faces without any groove gaps, the through hole of the pipe (1) (2) is only filled with welded metal, that is, only one side of the reinforcing bar is welded, so the strength is low and there is a safety problem.

In order to make the reinforcing bars (5) (5) face each other with a defined groove gap W in the pipe (1), a jig (7) as shown in FIG. 8, for example, is required.

The jig (7) has a pair of clamp stands (72073) arranged on a guide rod (71) so that they can approach and separate from each other, and a screw shaft (7).
4) One end is rotatably fitted into one clamp base (72), and the other end is penetrated and screwed into the clamp base (73).

Place one end of each of the two reinforcing bars (5) (5) on both clamp stands (72) (73), and tighten the clamp screws (75076).
Clamp the reinforcing bars (5) (5) by.

Rotate the screw shaft (74) to increase the screw thrust and adjust the gap between both clamp stands (72) (73), and then tighten the reinforcing bars (5) (5).
) on the screw shaft (74).
Adjust to the appropriate dimensions while checking 7).

After that, the pipe (which one had fitted in advance to the end of one of the reinforcing bars)
1) Slide it toward the groove side and perform welding as described above.

However, as described above, determining the groove gap using the jig (7) takes time and effort, and the workability is extremely poor.

For this reason, welding work is often performed without using the jig (7), resulting in variations in the groove gap, or welding is performed without any groove gap at all, resulting in a welded joint as described above. reliability will be lost.

Just by looking at the state in which the through hole (2) of the pipe (1) is filled with welded metal, it is difficult to determine whether or not a groove gap has been formed in the opposing surfaces of the reinforcing bars, and whether the groove gap is filled with welded metal. It is not possible to determine whether there is one or not.

It is possible to inspect the welding condition of the joint by non-destructive inspection using radiography or ultrasonic flaw detection.

However, in civil engineering and construction sites, there are a huge number of reinforcing bars to be connected, and it is impractical to perform the above-mentioned non-destructive inspection in terms of time and cost.

Further, at a reinforced concrete construction work site, a hoop (8) is fixed to a reinforcing bar frame (51) as shown in FIG. 9.

This is made by assembling a plurality of reinforcing bars (5) vertically in a frame shape, and the frame (
51), a hoop (8) formed by bending a reinforcing bar into a rectangular shape is fitted at a predetermined interval, and the hoop (8) is fixed to the reinforcing bar (5) with a wire.

When connecting reinforcing bars vertically using the conventional pipes (5) shown in Figures 6 and 10, if the butt part of the reinforcing bars and the pipe are not welded, the pipe will fall down and support the reinforcing bars above. I can't do that.

Therefore, the 7-p cannot be installed until the welding work is completed.

Since the welding operator and the hoop installation are carried out by different professionals, the hoop installation operator has to wait during the welding work, resulting in poor work efficiency.

Furthermore, when welding reinforcing bars vertically, the upper reinforcing bars hit the lower reinforcing bars under their own weight, so it is not possible to form a groove gap between the reinforcing bars without using the jig (7) described above.

[Means for solving problems]

The present invention solves the above problem by making it possible to correctly determine the groove gap between the reinforcing bars by simply inserting the reinforcing bars from both ends of the pipe.

The configuration of the present invention corresponds to the opening of the through-hole (2) at approximately the center of the pipe (1) for a pipe (1) in which the welding through-hole (2) is opened at only one location. Then, a stopper (3) having a width approximately equal to the groove gap between the reinforcing bars protrudes from the inner surface of the pipe.

[Action and effect]

Insert reinforcing bars from both ends of the pipe (1) and attach the stopper (3)
Apply to.

A groove gap W is reliably formed between the reinforcing bars corresponding to the width of the stopper (3).

You are free from the trouble of adjusting the groove gap using a jig as in the past, and when welding in a downward position with the reinforcing bar lying on its side, only the through hole (2) for welding the pipe can be used without filling the groove gap. Since it is impossible for the groove to be filled with molten metal, welded joints using the pipe with stopper (1) of the present application can be guaranteed to be filled with molten metal without the need for non-destructive testing, and are reliable in terms of strength. A joint with high properties can be realized.

In addition, when using the pipe with a stopper of the present invention, when the two reinforcing bars (5) (5) are fitted vertically at both ends of the pipe, the stopper (3) of the pipe (1) prevents the pipe itself from slipping down. The reinforcing bar can be erected almost straight with the end of the reinforcing bar fitted into the pipe.

Therefore, the hoop (8) can be attached even if the welding work is not completed, eliminating the loss of waiting time for the worker winding the hoop, and improving the workability of the reinforcing steel framework.

17 = [Example] The pipe (1) of the example is made of reinforcing bars (5) with an outer diameter of about 25 mm (
5) Although the present invention is for joining, it is not limited to this, and it goes without saying that it can be applied to welding joints of various reinforcing bars.

The above pipe (1) is made of SK41 material and has an outer diameter of approximately 4511II.
111 Approximately 60 long seamless pipes with an inner diameter of approximately 30 mm
It is cut to a length of mm, and a through hole (2) for welding is provided at only one location approximately in the center of the peripheral wall.

A stopper (3) is placed approximately in the center of the inner surface of the pipe (1).
) is provided.

The stopper (3) is a protrusion extending in the circumferential direction with a width of approximately 71flI11 and formed integrally with the pipe (1), and both ends of the protrusion are aligned with the hole line of the welding through hole (2). has reached.

Both ends of the pipe (1) are largely chamfered to form gentle slopes (4) (4) and taper.

Therefore, reinforcing bars (5) (5) are fitted from both ends of the pipe (1) and brought into contact with the stopper (3).

As a result, there is a stopper (3) between the reinforcing bars (5) (5).
) is formed.

A welding wire (not shown) is inserted through the through hole (2) of the pipe (1), carbon dioxide shield welding is performed, and the groove gap is filled with molten metal. Furthermore, the hole (2) is filled with molten metal while welding the entire circumference of the hole line of the through hole (2) to the reinforcing bars (5) (5).

When welding in a downward position with the reinforcing bars facing sideways, the molten metal fills the groove gap W from the bottom to the top, preventing any space from existing between the groove gaps W, and welding the reinforcing bars (505
) firmly attached.

Although there is only one through hole (2) for welding, the hole (2)
The opposite side is almost unaffected by high temperatures during welding, and the joint strength can be avoided from deterioration caused by extensive thermal effects, making it possible to construct a high-strength joint part.

Furthermore, since the opposite side of the through hole (2) is closed, the weld metal will not melt.

As shown in Figure 9, when connecting reinforcing bars vertically to form a reinforcing bar frame (51) of a concrete structure, reinforcing bars (5) (5)
Just by fitting the 7-pipe (8) into the reinforcing bar frame (51), the pipe will not fall down and the reinforcing bar itself will not fall down.
) can proceed regardless of whether or not the hoop (8) has been welded, and there is no need to wait until the operator finishes welding after assembling the hoop (8).

Also, when setting the hoops at approximately equal intervals by fitting the necessary 7-hoops (8) to the top of the frame (51) like a two-point chain and crossing the reinforcing bars (5), the end of the pipe (1) Since the section is largely chamfered and has a slope (4), the hoop (8) is attached to the reinforcing bar (5).
) When pushed in the axial direction of the pipe (8), the bar (8) rides on the slope (4) of the pipe (1) and moves over the pipe (1) while bending the reinforcing bar itself inward. As a result, the end face of the pipe and the hoop do not come into contact with each other and prevent the hoop from sliding.

The following table [1] shows the appropriate pipe size for the reinforcing bar thickness.

(Leaving space below) Table [I] Standard size table for pipes The following table (n) is strength test data of welded joints when reinforcing bars were connected by carbon dioxide shield welding using pipes based on the standards in Table [I] above. be.

*The material of the reinforcing bars is 5D35, and the material of the pipe is SK41. *The welding wire used has a yield point of 55 kgf/mm2 and a tensile strength of 64 kgf/+om2. *The criterion for determining the fracture position is from the center point of the groove spacing. The distance to the fracture position determines whether the weld is fractured or the base metal is fractured; if it is less than the numerical value, it is determined that the weld is fractured, and if it is greater than the numerical value, it is determined that the base material is fractured.

(The following is a blank space) In carrying out the present invention, as shown in Fig. 4, a pipe (1
) If one or more notches (31) are made in the stopper (3) on the inner surface, the area of the joint between the end face of the reinforcing bar and the welded metal increases, and the pipe (1) is cut out from the notch (31). ) The molten metal flows between the inner surface of the pipe and the reinforcing bar, further strengthening the bond between the reinforcing bar and the pipe.

Furthermore, the through hole (2) of the pipe (1) is cut with an end mill or the like.
It is also possible to open a long hole extending in the narrow direction as shown in Figure 0.

Alternatively, a plurality of pipes may be arranged horizontally in a row on a slide table, the slide table may be moved, and a rectangular through hole (2) as shown in FIG. 5 may be provided in each pipe.

Further, the stopper (3) is not limited to the above-mentioned one, and as shown in Fig. 5, a metal piece (52) may be bent into a U-shape and fixed to the inner surface of the pipe (1) by spot welding or the like. It is possible.

[Brief explanation of drawings]

Fig. 1 is an oblique view of a pipe for a welded joint, Fig. 2 is a sectional view of a welded joint, Fig. 3 is a sectional view taken along line I-I [1] of Fig. 4, and Fig. 4 is a sectional view of another embodiment. Cross-sectional view of pipe for welded joint,
Fig. 5 is a perspective view of a pipe for a welded joint showing another example of a stopper and a through hole, Fig. 6 is a perspective view of a pipe for a welded joint previously proposed by the applicant, and Fig. 7 is a perspective view of the same pipe as described above. Figure 8 is a front view of the welding jig, Figure 9 is a slope view of the reinforcing bar frame, Figure 10 is a slope view of a conventional welded joint pipe, Figure 11 is a cross-sectional view of the welded joint used. FIG. 3 is a sectional view of a welded joint using the same pipe as above. (1)...Pipe (2)...Through hole (3)
...Stopper (4)...Slope (5)...Iron
Line = 15- Figure 1 Figure 7

Claims (1)

[Claims] [1] Two reinforcing bars (5) (5) to be joined by welding
In a welded joint pipe in which a through-hole (2) for welding is opened at only one location approximately in the center of the cylindrical wall of the pipe for a pipe (1) with openings at both ends into which the ends of the pipe fit, Pipe (1
), a stopper (3) with a width approximately equal to the groove gap between the reinforcing bars protrudes from the inner surface of the pipe, corresponding to the opening of the through hole (2), and a stopper (3) with a width approximately equal to the groove gap between the reinforcing bars is protruded from the inner surface of the pipe, and the length of the two reinforcing bars is extended. A pipe for a welded joint, which is characterized by regulating the flow rate and forming a groove gap between reinforcing bars. [2] Both ends of the pipe (1) are sloped (4) (
4) Claim 1 is tapered as follows.
Pipe for welded joints as described in section.