JPS5916873B2 - electric resistance welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric resistance welding device, and more particularly, to
This invention relates to a device that heats a V-shaped opening of a material to be welded with an electric current, pressurizes it with a pressure device, and welds it by pressure.

In general, induction type and contact type electric resistance welding devices are generally used.

The induction type, as schematically shown in Figure 6A, has an induction coil 4 placed in front of the welding part 3 of the welded material 2 having a rectangular opening 1, and a current is passed through the induction coil 4 to Material 2
The welding part 3 is heated by the heating action of the induced current that is secondarily induced in the welding part 3, and the welded part 3 is pressurized and pressed by a pressurizing device 5 such as a squeeze roll, and the path of the induced current i is as follows.
It flows along the V-shaped opening 1 as shown in FIG. 6B. However, compared to the contact method, this method has the advantage that the surface of the welded product is not damaged and there is no wear and tear; however, it is difficult to weld medium and large diameter pipe products. The disadvantage is that it is inefficient. In addition, the contact type welding device is similar to the induction type in that the welding part 3 of the welded material 2 is pressurized by the pressure device 5, but the current is applied to the welded material 2. The difference is that the current is passed directly through the electrode, and the method of supplying current to the welding part is that one uses a rotating disk electrode 6 as shown in Figure 1A, and the other uses a contactor T as shown in Figure 8A. There was something there.

In the case of using a rotating disk electrode 56, the outer peripheral surface of the rotating disk electrode 6 contacts the upper surface or the front of the welding part 3, and the current i is
As shown in Figure B, the current flows along the V-shaped opening 1 from the top or front of the welding part 3, and due to the proximity effect, the current also flows to the opposing abutting surfaces of the welding part 3 and is heated. On the upper surface of the welding part 3 where the outer peripheral surface of the plate electrode 6 comes into contact,
There are problems in that damage caused by sparks and scratches caused by roughness of the outer circumferential surface of the electrode occur. Furthermore, there is a problem that heat generating parts are generated at two places i5 between the rotating disk electrode 6 and the welding part 3 and between each welding part 3 and there is a lot of loss. It is difficult to set welding conditions. In the case where the contact T is used, the current i supplied from the contact T which contacts the upper surface of the welding part 3 flows in the same way as in the case where the rotating disk electrode 6 is used as shown in Fig. 8Bj0. Similar to the former case, there are problems such as damage to the surface of the product due to sparks and scratches due to the roughness of the contact surface of the contactor 7, and rapid wear of the contactor T.

j5 The present invention has been made in view of the above-mentioned problems, and aims to provide an electric resistance welding device that is efficient and does not cause damage such as scratches on the surface of the product. Examples will be described in detail.

FIG. 1 is a perspective view schematically showing an electric resistance welding device 8 according to the present invention, in which a welded portion 10 of a material 9 to be welded such as an electric resistance welded pipe is shown.
Pressure devices 11, such as squeeze rolls, are disposed on both sides of the welded portion 10 to press and press the welded portion 10.

The material to be welded 9 is transported by an arrow C by a transport device (not shown).
The material is fed in the direction. For electric resistance welded pipes, etc., a flat hoop is formed into a circular shape, and a V-shaped opening 12 determined by the forming method is opened in a V-shape, and a seam guide or the like is generally inserted to stabilize the opening. However, in the present invention, the disc-shaped electrode 13, which also serves as a seam guide, is connected to the V-shaped opening 12.
It has been inserted into. Therefore, the electrode 13 has good conductor electrode plates 15 bonded to both sides of a disc-shaped insulating material 14. Being squeezed. The disk-shaped electrode 13 is rotatably provided at its center via a pivot (not shown) perpendicular to the material feeding direction, and the electrode plates 15 on both sides are provided with a high-frequency current. Each phase of a single-phase power supply is energized, but the frequency is not particularly limited. A clamping device 17 is disposed near both sides of the electrode 13 to clamp the material to be welded 9 with a constant pressure.

The clamping device 17 uses rollers 18 and 19 that press the contact pressure between the electrode 13 and the workpiece 9 to an appropriate value. Therefore, the rollers 18 and 19 are arranged perpendicular to the electrode 13. Although not shown, the rollers 18 and 19 are pressurized by a hydraulic cylinder or a spring tightening screw. Figures 2, 3 and 4
The figure shows another example of the shape of the electrode. The electrode 20 shown in FIG. be.

The electrode 23 shown in FIG. 3 has a tapered portion 26 formed at the tip of an electrode plate 25 bonded to both side surfaces of an insulating material 24 depending on the state of contact with each abutting surface 16 of the V-shaped opening 12. In the electrode 27 shown in FIG. 4, a stepped portion 30 is formed at the tip of each electrode plate 29 bonded to both sides of the insulating material 28, so that it can be used even when the opening degree of the V-shaped opening 12 is small. I have made it possible. In this case, the horizontal part of the stepped portion may be brought into contact with the upper surface of the material to be welded 9 for more stable use.
With the above configuration, when each phase of the single-phase power supply is energized to each electrode plate 14 of the electrode 13 inserted into the V-shaped opening 12 and pressed by the abutting surfaces 16 at a constant pressure, the V-shaped As shown in FIG. 5, a current 1 flows along the shape of the V-shaped opening 12 near the surface of the abutting surfaces 16 facing each other in the opening 12, and the proximity effect of this current causes each abutting surface 16 to directly heated.

Then, the material to be welded 9 is fed by a conveying device, and is pressed and welded by a pressure device 11. As described above, the present invention provides a device that heats a V-shaped opening by applying electricity, pressurizes it with a pressure device, welds it by pressure, and welds an electrode by interposing an insulating material in the V-shaped opening in front of the pressure device. Insert the electrodes with the plates bonded together, and apply the above V to each electrode plate of the electrode.
A pressure device is provided on both sides of the electrode so that the abutting surfaces of the shaped openings can be brought into contact with each other, and can press the material to be welded with a constant pressure from a direction perpendicular to the electrode. Since the abutting surfaces of the V-shaped openings that are pressurized and welded by the welding machine are directly heated, it is more efficient than any conventional welding device, and since there are no current-carrying parts on the top of the product, no scratches occur, and Even if damage occurs to each mating surface due to contact with the electrode, it will be absorbed by the part that is pushed out as a bead on the inner and outer surfaces when pressed by the pressurizing device, so there is no risk of leaving scratches on the product. It has a significant effect such as no. Although the present invention has been described using a disk-shaped electrode, it is also possible to use a flat plate as shown in FIGS. 2 to 4. In addition to welding pipes such as electric resistance welded pipes, the present invention can also be applied to welding flat plates, shaped steel, etc. that have a V opening.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a perspective view schematically showing an electrical resistance device according to the present invention, FIG. 2, and FIG.
4 and 4 are partially enlarged views showing other embodiments of the shape of the tip of the electrode, FIG. 5 is an explanatory diagram of the current path of the device according to the present invention, and FIG. 6A is a conventional inductive electric resistance. FIG. 6B is an explanatory diagram of the current path in FIG. 6A, FIG. 7A is a schematic perspective view of a conventional contact electric resistance welding device using a rotating disk electrode, and FIG. 7B is a schematic perspective view of the welding device. 7A
8A is a schematic perspective view of a conventional contact type electric resistance welding device using a contactor, and 8B is an explanatory diagram of the current path in the figure.
The figure is an explanatory diagram of the current path in FIG. 8A. 11... Pressure device, 12... V-shaped opening box... Electrode, 14... Insulating material, 15...
... Electrode plate, 16 ... Butt surface, 17
...Press device.

Claims (1)

[Claims] 1 The V-shaped opening is heated by electricity, and the electrode plate 15 is welded by pressing and welding with a pressure device, with an insulating material 14 interposed in the V-shaped opening 12 in front of the pressure device 11. The electrodes 13 bonded to each other are inserted and provided, and the electrodes 1
Each electrode plate 15 of No. 3 is brought into contact with each abutting surface 16 of the V-shaped opening 12, and the material to be welded 9 can be freely clamped on both sides of the electrode 13 from a direction perpendicular to the electrode 13 with a constant appropriate pressure. An electric resistance welding device characterized in that it is provided with a clamping device 17.