JPH07227675A - Lap seam welding equipment - Google Patents

Abstract

PURPOSE:To enable welding of the ends of superposed steel strips without melting the aluminum of the part where comes into contact with a rotary electrode by structuring electrodes with a lower electrode and a rotary electrode and using pure copper for the material of the rotary electrode. CONSTITUTION:Lap seam welding is performed while rolling a rotary electrode 19 in a direction vertical to a paper face on steel strips 1a, 1b superposed on a lower electrode 18. Since the material of the rotary electrode 19 is formed with pure copper having little electric resistance, heat generation is less than heretofore at the contact part between the rotary electrode 19 and a 7000 series aluminum 20, lowering the surface temperature of the steel strips 1a, 1b that are in contact with the rotary electrode 19. Additionally, the cross-sectional shape of the outer periphery of the rotary electrode 19 is made semicircular, the area of the energizing part is made smaller, and thereby heat generation concentrates on a joint part between the steel strips 1a, 1b, and lap seam welding is performed stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lap seam welding apparatus for overlapping and welding end portions of a metal strip in the length direction.

[0002]

2. Description of the Related Art A pipe material is manufactured by the process shown in FIG. The strip 1a wound around the support shaft 10 is formed into an electric resistance welded pipe through the lap seam welding device 2, the hoop cage 3, the welding means 4, the annealing means 5 and the adjusting means 6,
The pipe 8 is cut by the dividing means 7. Strip 1a
The support shaft 10 integrally attached to the vertical shaft 9 together with the strip plate 1b.
The strips are wound around both ends of the strip and the strip to be supplied can be replaced by rotating the vertical shaft 9 by 180 °. The lap seam welding device 2 places the rear end of the strip 1a and the front end of the strip 1b on the strip 11 when the strip 1a is removed and then the strip 1b is supplied. Rotate the rotating electrode on top of it and press the overlapped part,
It is to energize and perform lap seam welding. 1
Reference numerals 2 and 13 are rollers. The hoop cage 3 has rolls 14 for continuously performing electric resistance welding of the pipe material formed by the welding means 4 located downstream of the hoop cage 3 while the strips are overlapped and welded by the lap seam welding device 2. Increase the distance between 15 and stock the strip 1a,
The strip 1a is supplied by reducing the distance between the strips 15. The welding means 4 is adapted to perform welding while applying a high-frequency current to both sides of the strip 1a, which are V seams that are sequentially butted against each other as the belt travels. The annealing means 5 is for induction heating while moving the pipe material welded by electric resistance welding. The adjusting means 6 adjusts the dimensions of the pipe material and corrects the bend, and 6a is a cooling means. 7a in the dividing means 7 indicates a cutter.

By the way, plate joining in the lap seam welding apparatus 2 is performed as shown in FIG. First, FIG.
As shown in (a), the ends of the strips 1a and 1b are cut obliquely along cutting lines parallel to each other. This disconnection is done simultaneously. Next, both ends of the strips 1a and 1b are overlapped with each other to form a lap seam weld 16 at the center of the overlapped portion as shown in FIG. 3 (b). Then, during welding, the protruding portion 17 is generated as shown in FIG. 3C due to the pressure of the rotating electrode, so the protruding portion 17 is cut off as shown in FIG. 3D.

Details of lap seam welding are shown in FIG. The strips 1a and 1b are 300 that serve as the base of the pipe material.
Clad consisting of three phases: 0 series aluminum 21, 7000 series aluminum 20 which has a corrosion preventing effect because it is on the inner surface side of the pipe material, and 4000 series aluminum 22 which can be brazed because it is on the outer surface side of the pipe material. Formed on the material. As shown in FIG. 4, after the front end of the strip 1b is overlaid on the rear end of the strip 1a, a disc-shaped rotary electrode 19 made of chrome copper and having a width W = 5 mm is rolled in a direction perpendicular to the plane of the drawing. Lap seam welding is performed by applying electricity between both electrodes while pressing the strip plates 1a and 1b between the strip-shaped lower electrode 18 made of chromium copper on the strip 11. Here, the lower electrode 18 and the rotary electrode 19 are formed of chromium copper because chromium copper has excellent strength, surface hardness, and durability.

[0005]

However, as can be seen from Table 1 showing the magnitude of electric conductivity of each material, assuming that the electric conductivity of pure copper is 100, the resistance of 7000 is large.
The most heat is generated in the part of the system aluminum 20, so that not only the joints with the strips 1a and 1b but also the temperature in contact with the rotary electrode 19 is significantly increased. And melted 70
The 00 series aluminum 20 adheres to the rotary electrode 19 and changes the welding conditions, making stable lap seam welding impossible. Also,
The molten aluminum adheres to the rotary electrode 19, so that the current-carrying performance is lost.

[0006]

[Table 1]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lap seam welding apparatus that solves the above problems.

[0008]

The structure of the present invention for achieving the above-mentioned object includes a lower electrode and a lower electrode in which end portions of strips connected to each other are superposed on each other. In a lap seam welding apparatus composed of a rotary electrode that is energized by rolling while pressing while sandwiching a part where a pair of strips are overlapped with each other, pure copper is used as a material of the rotary electrode.

[0009]

[Operation] When pressure and current are applied by sandwiching the overlapping strip between the rotating electrode and the lower electrode, the rotating electrode in the strip is made of pure copper, which has little resistance and generates a small amount of heat. The part that comes into contact with will not melt and adhere to the rotating electrode.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

The construction of the lap seam welding apparatus according to the present invention is shown in FIG. In the present invention, the rotary electrode 19 which is conventionally made of chromium copper is made of pure copper. Further, although the outer diameter dimension of the rotary electrode 19 is conventionally the same along the width direction, in the present embodiment, the outer peripheral portion has a semicircular cross-sectional shape, and the outer diameter dimension on both sides is the central outer diameter dimension. Is smaller than. That is, the width dimension of the rotary electrode 19 is W = 5 mm, while the dimension of the semicircular cross section of the outer peripheral portion is 2.5R.

Next, the operation of such a lap seam welding device will be described. Strips 1a, 1 stacked on the lower electrode 18
When the lap seam welding was performed while rolling the rotary electrode 19 in the direction perpendicular to the paper surface on b, the rotary electrode 19 was formed of pure copper having a low electric resistance.
The heat generated at the contact portion between the 9 and the 7000 series aluminum 20 is smaller than in the conventional case, and the cross-sectional shape of the outer peripheral portion of the rotating electrode 19 is made semicircular to reduce the area of the conducting portion.
Heat is concentrated at the joint portion of 1b, and lap seam welding is performed stably.

In this embodiment, the strip is made of aluminum clad material, but the material is not limited to aluminum.

[0014]

As can be seen from the above description, according to the lap seam welding apparatus of the present invention, since pure copper is used as the material of the rotating electrode, the electrical resistance is reduced and the surface of the strip contacting the rotating electrode is reduced. The temperature drops. Therefore, unlike the conventional case, there is no problem that the molten aluminum adheres to the rotary electrode and the current-carrying performance is deteriorated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a lap seam welding apparatus according to the present invention.

FIG. 2 is a configuration diagram of an apparatus for manufacturing a pipe material.

FIG. 3 is an explanatory view showing a procedure for connecting the metal strips.

FIG. 4 is a configuration diagram of a conventional lap seam welding device.

[Explanation of symbols]

 1a, 1b ... Strip plate 20 ... 7000 series aluminum 21 ... 3000 series aluminum 22 ... 4000 series aluminum 18 ... Lower electrode 19 ... Rotating electrode

Claims (1)

[Claims] 1. A lower electrode and end portions of strips connected to each other on the lower electrode are superposed on each other, and the superposed portion of a pair of strips is sandwiched between the lower electrode and the rolls while applying pressure. In a lap seam welding device consisting of a rotating electrode that is energized by electricity, the material of the rotating electrode is pure copper.
Seam welding equipment.