JPH06262354A - Method for mutually joining steel bars - Google Patents

Abstract

PURPOSE:To provide the method, for mutually joining steel bars in which joining of good quality is performed with a good work efficiency. CONSTITUTION:Two pieces of ferrule 1, 2 are abutted and fitted on the outer circumference of the abutting end parts of two steel bars 5, 6; after an arc is generated between the abutting end parts, one steel bar is moved in retreat from the other steel bar by a prescribed distance; while the air in the inside space of the ferrule is discharged from the notched parts 7, 8 in the end face of the ferrule by an arc pressure, the abutting end parts are welded. The pool of this molten metal is reserved in the inside space of the ferrule; immediately before stopping the arc after a prescribed time, one steel bar is advanced and pushed in the pool of the molten metal; after a welding bead is formed which is prescribed in the inner wall surface of each ferrule 1, 2, the ferrules 1, 2 are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining steel rods such as building reinforcing bars in the longitudinal direction.

[0002]

2. Description of the Related Art As a general joining method for steel rods, there are a gas pressure welding method and a mechanical joint. This gas pressure welding method involves heating each joint end of the butted steel rods with a gas flame and then pressurizing and joining the steel rods in the longitudinal direction. However, it takes a long time to heat and the work efficiency is poor. Not only that, since there is no gap on the abutting end faces, it is necessary to carefully process the end faces, and the joining quality is unstable.

In mechanical joints such as screw joints and mechanical joints, since it is necessary to screw the joint end portion of the steel rod, the work efficiency is poor and the joint strength is generally low.

[0004]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a method of joining steel rods which enables high quality joining with high work efficiency.

[0005]

In the following, in the joining method of the present invention, two ferrules 1 and 2 are butted so that inner spaces 3 and 4 communicate with each other. The butt end 5 of the two steel rods 5 and 6
After fitting to the outer periphery of a and 6a and generating an arc between the butt ends 5a and 6a by supplying a required current,
One steel rod 5 is moved backward from the other steel rod 6 by a predetermined distance.

While discharging the air in the inner spaces 3 and 4 of the ferrules 1 and 2 from the notches 7 and 8 of the ferrule end face by the arc pressure, the butt ends 5a and 6a are melted by the arc heat, and the pool of this molten metal is melted. While keeping the arc in the inner space 3, 4 of each ferrule, the steel rod 5 is moved forward toward the other steel rod 6 by moving one steel rod 5 toward the other steel rod 6 immediately before the arc is stopped after a predetermined time. After the welding bead 9 having the required height and width defined by the inner wall surfaces of the ferrules 1 and 2 is formed, the ferrules 1 and 2 are removed.

[0007]

EXAMPLE In the example shown in FIGS. 1 to 3, each ferrule 1 and 2 is made of a heat-resistant porcelain material in a cylindrical shape. As this porcelain material, for example, SiO ₂ : 60.
2, Al ₂ O ₃ : 23.8, CaO: 3.4, MgO:
9.7, FeO: 1.29, TiO ₂ : 1.0, Na:
A cordierite material blended with 0.2, K: 0.6 is used, but the materials and components are not particularly limited thereto. The ferrules 1 and 2 are formed by appropriately adjusting the dimensional accuracy of the inner peripheral surface so that the fitting gap with the steel rods 5 and 6 is, for example, about 0.3 mm.

The abutting end faces 1a of the ferrules 1 and 2,
Notches 7 and 8 are radially provided on a part of the circumference of 2a,
The notches 7 and 8 are open on the inner and outer side surfaces of the ferrules 1 and 2. When joining the steel rods 5 and 6 arranged sideways as shown in FIG. 1, the ferrules 1 and 2 have the notches 7 and 8 so that the molten metal does not drip from the notches 7 and 8. 8 is attached so that it may come up.
In a normal usage mode, the ferrules 1 and 2 are held in the initial mounting positions by the frictional force acting between the steel rods 5 and 6, but the fasteners are mounted across the steel rod and the ferrule. It can also be positively fixed and held by such as.

The steel rods 5 and 6 are clamped and held at the abutting positions by the clamp means 11 and 12 mounted on the main body 10 of the welding machine. One of the clamp means 11 is the welding machine body 10.
It is configured to be able to move back and forth along the rail 13 of the. A small rod 18 made of aluminum is embedded in the center of the abutting end 5a of one of the steel rods 5 to serve as an arc start and a deoxidizer. When a required welding current is supplied from the welding power source 15, an arc is first generated between the small rod 18 and the steel rod 6. A deoxidizing and refining agent can be separately attached to the steel rods 5 and 6.

One of the steel rods 5 is moved back and forth by a servomotor 14 with an encoder connected to an arc detector and an arithmetic processing unit at a required timing and speed set in relation to the generation and stop of the arc. . The operation of pushing the steel rod 5 into the pool of molten metal can be carried out in a single step by moving it forward to the required depth at the same speed, but it is moved forward at high speed until it reaches the pool surface of molten metal, and then When adopting the two-step pushing method of moving forward at a low speed and pushing to the required depth, it is possible to accurately move the steel rod to the required position without disturbing the pool before the molten metal solidifies, so high quality welding is possible. The bead 9 is obtained more reliably.

After the welding is completed, the clamping means 11 and 12 are released, and the ferrules 1 and 2 are crushed and removed. As a result, the weld bead 9 having the required height and width determined by the inner wall surfaces of the ferrules 1 and 2 appears in the welded portion, as shown in FIG.

In the alternative embodiment shown in FIGS. 4 and 5, the steel rods 5, 6 are arranged vertically. The notches 7 and 8 are radially provided on the entire circumferences of the abutting end faces 1a and 2a of the ferrules 1 and 2, and the notches 7 and 8 are open to the inner surface and outer surface of the ferrules 1 and 2. A stopper means 16 is fitted on the steel rod 6 and fixed to the steel rod 6 by tightening a set screw 17. The stopper means 16 contacts the lower end surface of the ferrule 2 and holds the ferrules 1 and 2 at predetermined positions.

The steel rods 5 and 6 are clamped and held in the abutting position by suitable clamping means of the welder main body, as in the case of the above-mentioned sideways joining. The clamp means holding the steel rod 5 moves back and forth along the rail of the main body of the welding machine. A small rod 18 made of aluminum is embedded in the center of the abutting end 6a of the steel rod 6 to serve as an arc start and a deoxidizer. When a required welding current is supplied, an arc is first generated between the small rod 18 and the steel rod 6. A deoxidizing and refining agent can be separately attached to the steel rods 5 and 6.

The forward and backward movement of one steel rod 5 is performed by the servomotor with an encoder at the required timing and speed set in relation to the generation and stop of the arc, as described above. The operation of pushing the steel rod 5 into the molten pool can be performed in a single step or in two steps as described above.

After the completion of welding, each clamp means is released,
After removing the stopper means 16, the ferrules 1 and 2 are removed by breaking. As a result, the weld bead 9 having the required height and width determined by the inner wall surfaces of the ferrules 1 and 2 appears in the welded portion. The driving means for moving the steel rod back and forth is not limited to the servomotor, but an air cylinder, a spring, or the like can be used. Further, as each ferrule, two pieces that are divided into semi-cylindrical shapes can be used as a set.

When the two-step pushing method is adopted, for example, if the diameter of the steel rod is 22 mm and the welding current is set to 1850 A, the distance of backward movement of the steel rod is 2 mm and the backward movement speed is 100 mm / sec. Yes, the arc duration is 0.8 sec, the distance of the first-stage pushing operation of the steel rod is 3.0 mm, the forward speed is 200 mm / sec, the distance of the second-stage pushing operation of the steel rod is It is 3.5 mm and the forward speed is 30 mm / sec.

[0017]

As described above, in the method of the present invention, the steel rod 5,
Two ferrules 1 at the butt ends 5a, 6a of 6
2 are butted against each other, and an arc is generated in the inner spaces 3 and 4 of the ferrules 1 to bring the butted ends 5 into contact with each other.
a, 6a are melted, and the end of the steel rod is pushed into the pool of the molten metal to form the weld bead 9 defined by the inner wall surfaces of the ferrules 1 and 2. The joining can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a schematic right side view of a transverse joint of a steel rod and a welding machine in an embodiment of the method of the present invention.

FIG. 2 is a front view of a ferrule used for welding in FIG.

FIG. 3 is a right side view of the joined steel rods.

FIG. 4 is a right side view of a longitudinal joint portion of a steel rod according to another embodiment of the method of the present invention.

5 is a front view of the ferrule used for welding in FIG. 4. FIG.

[Explanation of symbols]

 1 Ferrule 2 Ferrule 3 Inner Space of Ferrule 4 Inner Space of Ferrule 5 Steel Bar 6 Steel Bar 7 Notch of Ferrule 8 Notch of Ferrule 9 Weld Bead 10 Welder Main Body 11 Clamping Means 12 Clamping Means 13 Guide Rail of Clamping Means 14 Servo Motor 15 Welding Power Supply 16 Stopper Means 17 Set Screw 18 Aluminum Rod

Claims (1)

[Claims] 1. The two ferrules are butted so that the inner spaces communicate with each other, and fitted to the outer circumferences of the butted ends of the two steel rods, and an arc is provided between the butted ends of the steel rods by supplying a required current. Then, one of the steel rods is moved backward from the other steel rod by a predetermined distance, and the air in the space inside the ferrule is discharged from the notch of the ferrule end face by the arc pressure, while the arc heat causes The butt ends are melted, and the pool of molten metal is stored in the inner space of the ferrule to continue the arc, and one steel rod is moved forward toward the other steel rod immediately before the arc is stopped after a predetermined time. The ferrule is removed after the weld bead of the required height and width defined by the inner wall surface of each ferrule is formed by pushing into the pool of molten metal. Joining method.