JPH08215892A - Steel sleeve for weld joint of reinforcement - Google Patents

Abstract

PURPOSE: To provide a steel sleeve for a weld joint which is simple in structure and free from any melting-down of the weld metal or defective welding in the welding, especially, the welding by the gas shielded arc welding method. CONSTITUTION: In a steel sleeve for a weld joint of a reinforcement, an opening part 2 is provided at the center of a tubular body 1, a weld metal receiver 3 is integratedly provided on the opening part 2 with the tubular body 1, a notched groove 4 is provided between the tubular body 1 and the weld metal receiver 3, and the weld metal receiver 3 is opened in the U-shape. The weld metal receiver 3 is opened in the U-shape with 0-30 deg. outwardly relative to the vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel sleeve used for joining reinforcing bars to each other by gas shielded arc welding.

[0002]

2. Description of the Related Art As a method of joining reinforcing bars, there are methods such as gas pressure welding, welding joints and mechanical joints. As a method using the above-mentioned welded joint, a steel sleeve having a notch hole having the same shape as or a similar shape to the groove portion of the strip (reinforcing bar) described in JP-B-47-18403 (Figs. 6a and 6b).
Welding with a covered arc welding rod using. Further, in Japanese Examined Patent Publication No. 4-20796, a reinforcing bar is surrounded by a copper metal, a shielding gas is caused to flow from the upper part of the gold and welded by a gas metal enclosure, and a welding is performed in a predetermined area on the edge side of the joint surface. A method of welding by reducing the heat input. Further, Japanese Patent Laid-Open No. 3-35897 discloses a method of welding using a ceramic backing material.

However, in recent years, reinforced concrete structures have become higher and larger in size, and the reinforcing bars applied thereto have a larger diameter and higher tensile strength, and a more efficient welding method is required. In response to this demand, the welding efficiency is extremely poor in the construction using the covered arc welding rod described in JP-B-47-8403. Further, when the steel sleeves shown in FIGS. 6A and 6B are used to join by a gas shield arc welding method that can obtain a high welding amount, the weld metal will be burned down from the cutout holes 7 during welding. If the welding current is lowered so that the weld metal does not melt down, the efficiency is deteriorated as in the case of welding with a covered arc welding rod.

Further, in the method of gas shielded arc welding (gas-enclosed welding) using a copper alloy in Japanese Patent Publication No. 4-20706, the welding time is short, but it takes time to set the copper alloy. A device for controlling the amount of welding heat input is also required, which causes a problem in terms of cost. Furthermore, when gas shielded arc welding is performed using the ceramic backing material disclosed in JP-A-3-35897, the ceramic material is not energized, which hinders the starting of the arc or makes the arc unstable during welding, resulting in welding defects. It tends to occur.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a steel sleeve for a welded joint, which is simple and does not cause weld metal burn-through or welding defects in the welding of reinforcing bars, especially in the gas shielded arc welding method. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION A gist of the present invention is to provide a steel sleeve for a welded joint of a reinforcing bar with an opening at the center of the tubular body, and the weld metal receiver is provided in the opening at the tubular body. And a notch groove between the tubular body and the weld metal receiver.
It is characterized by having an opening in shape. Further, the weld metal receiver is also characterized in that it is opened in a 0 to 30 ° U shape outward with respect to the vertical direction.

[0007]

FIG. 1 is a perspective view showing an example of the steel sleeve of the present invention.
2 (a), 3 (a) and 4 (a, b) are front views. 2B is a cross section taken along the line AA of FIG. 2A, and FIG. 3B is a cross section taken along the line BB of FIG. 2A. Also, FIG.
Shows an example of the case where a reinforcing bar is inserted in the steel sleeve of the present invention.

In the steel sleeve, an opening 2 is provided in the center of the tubular body 1, and a weld metal receiver 3 is integrally provided with the tubular body 1 in the opening 2. Further, the tubular body 1 and the weld metal receiver 3
The weld metal receiver 3 has a U-shaped opening with a notch groove 4 between and. Since the weld metal receiver 3 blocks the weld metal during welding, it does not melt down. Since the weld metal receiver 3 is U-shaped and is open to the outside by 0 to 30 ° with respect to the vertical direction, weaving is possible during welding, and both the reinforcing bar 5 and the weld metal receiver 3 are sufficiently melted.
A welded portion having excellent strength and ductility can be obtained without welding defects such as poor fusion.

Further, since the opening 2 is surrounded by the weld metal receiver 3 and the reinforcing bar 5, the gas shielding property during welding is improved, and welding defects such as pits and blowholes caused by the entrainment of air occur. There is no occurrence. Further, since the shielding property is good, it is possible to separately send the shielding gas to the opening 2 from other than the welding nozzle, and in this case, the weaving width can be increased, and a better joint can be obtained.

If the angle at which the weld metal receiver 3 is U-shaped and vertically opened is less than 0 °, the weaving of the torch during welding is performed even if the shield gas is separately sent to the opening 2 from other than the welding nozzle. Since the width is limited, sufficient penetration cannot be obtained in both the reinforcing bar 5 and the weld metal receiver 3, and welding defects such as poor fusion occur. On the other hand, when the angle exceeds 30 °, the weld metal melts down between the cut groove 4 and the weld metal receiver 3, and the gas shield property is deteriorated to cause welding defects such as pits and blow holes. Furthermore, since the opening becomes large, it takes a long time for welding and the efficiency becomes poor. The height of the weld metal receiver 3 is preferably about the height of the reinforcing bar to be inserted.

Further, as shown in FIG. 3 (b), the tubular body 1
If the split groove 6 having a width of about 5 to 15 mm is provided, the positions of the left and right reinforcing bars can be visually checked when the reinforcing bar 5 is inserted into the steel sleeve, which facilitates the positioning of the reinforcing bars. In the steel sleeve of the present invention, the tubular body inner diameter is about 3 to 10 mm larger than the rebar outer diameter, the length is 50 to 120 mm, the tubular body wall thickness is 4 to 12 mm, and the weld metal receiving width (cutting groove width) of the rebar to be inserted. It is preferable that it is equal to or wider than the groove width by about 50 mm.

Further, the steel sleeve of the present invention may be machined from a pipe-shaped steel or may be machined by pressing flat steel to finish it into a cylindrical shape. At this time, a notch groove is formed between the tubular body and the weld metal receiver. By providing the above, the weld metal receiver can be easily processed to have a diameter larger than that of the tubular body, and can be easily manufactured.

[0013]

[Examples] Different diameter rebars having various outer diameters of SD390 specified in JIS G3112 were subjected to gas shield arc welding using steel sleeves of various shapes. The combinations are shown in Table 1. The welding wire is JIS Z3312 YGW21 1.
With a diameter of 2 mm, the welding conditions are downward welding (rebar horizontal) with a current of 200 to 280 A, voltage 28 to 35 V, horizontal welding (rebar vertical) with a current of 150 to 250 A, voltage 18 to 32 V, and carbon dioxide flow rate. It was set to 25 liters / minute, and a commercially available welding torch was used. The welding condition was investigated and a bending test was performed after welding using a jig having a radius of 2.5 times the outer diameter of the reinforcing bar. The results are summarized in Table 1.

[0014]

[Table 1]

In Table 1, Nos. 1 to 3 are examples using the steel sleeve of the present invention, and Nos. 4 to 7 are comparative examples. In Nos. 1 to 3 satisfying the requirements of the present invention, extremely good joints were obtained in which the weld metal did not melt down during welding and welding defects did not occur. No. 4 and No. 5 in the comparative examples
Had no weld metal receiver, so the weld metal melted down during welding and welding was stopped.

[0016] No. 6 is an O type whose weld metal receiving shape is a tubular body and is not opened in a U shape. Therefore, the welding torch cannot be weaved during welding, resulting in poor fusion at the joint portion and bending test. Sometimes it cracked and only turned up to 70 °.
For No. 7, the angle of the weld metal receiver was too wide, and the weld metal melted down between the weld metal receiver and the cut groove during welding, so welding was stopped.

[0017]

EFFECTS OF THE INVENTION According to the steel sleeve for welded joint of reinforcing bar of the present invention, it can be applied to the construction by the highly efficient gas shielded arc welding method, and it is simple and does not cause the weld metal to be burned down or defective. As a result, it is possible to greatly contribute to the efficiency of reinforcing bar joining.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a steel sleeve of the present invention.

FIG. 2A shows a front view of an example of a steel sleeve of the present invention. (B) shows the AA sectional view of (a).

FIG. 3A shows a front view of an example of a steel sleeve of the present invention. (B) shows the BB sectional view of (a).

4A and 4B are front views of another example of a steel sleeve according to the present invention.

FIG. 5 shows an explanatory view in which a reinforcing bar is inserted in the steel sleeve of the present invention.

6 (a) and 6 (b) are front views of a conventional steel sleeve example.

[Explanation of symbols]

 1 Tubular Body 2 Opening 3 Weld Metal Receiver 4 Notch Groove 5 Reinforcing Bar 6 Split Groove 7 Notch Hole

Front page continuation (72) Inventor Noburou Saeki 3-5-4 Tsukiji, Chuo-ku, Tokyo Nittetsu Welding Industry Co., Ltd. (72) Inventor Eiji Oshima 3-5-4 Tsukiji, Chuo-ku, Tokyo Nippon Steel Within Welding Industry Co., Ltd.

Claims (2)

[Claims] 1. A steel sleeve for a welded joint of a reinforcing bar, wherein an opening is provided at a central portion of a tubular body, and a weld metal receiver is integrally provided with the tubular body at the opening and the tubular body and the weld metal receiver are provided. A steel sleeve for a welded joint of a reinforcing bar, wherein a weld groove is provided between the weld metal receivers and the weld metal receiver is opened in a U shape. 2. The steel sleeve for a welded joint of a reinforcing bar according to claim 1, wherein the weld metal receiver is opened in a 0 to 30 ° U shape with respect to the vertical direction.