JPH11277248A - Seam welding electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable seamed state regardless of a straight line or curve by stabilizing a wire electrode, which is used in a wire seam welding method wherein seam welding is executed to the outer peripheral surface of a roller electrode via a copper wire, along a guide groove of the roller electrode, not deforming or disconnecting the wire electrode within the guide groove and moreover preventing a tendency of running around left and right of the wire electrode, in a seam welding equipment wherein an Al plated steel plate is held with a pair of opposing rotary roller electrodes and an electric current is supplied while rotating the steel plate. SOLUTION: A groove having a nearly W shaped cross section is provided in a guide groove for a wire electrode which is disposed in the outer peripheral surface of a pair of opposing rotary roller electrode 1, a cross section shape of the wire electrode in the side coming into contact with an object to be welded in the wire electrode 2 having a W shaped cross section in the side coming into contact along the groove is set to 4-6 mm in radius of curvature. Furthermore, a pair of opposing rotary electrode parts in a seam welding equipment for an Al plated steel plate is composed of a consumable wire electrode 2 being 50-80% of the peripheral length of the wire electrode in the contacting surface of the back face of the groove and the roller electrode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for seam welding in resistance welding, and more particularly, to a seam welding apparatus for clamping an object to be welded by a pair of opposed roller electrodes, energizing while rotating, and welding. The present invention relates to a seam welding electrode constituted by a roller electrode guide groove provided on the outer periphery of the opposed roller electrode and a consumable wire electrode received in the groove.

[0002]

2. Description of the Related Art As a member for a fuel tank of an automobile or the like, a molten Pb-Sn alloy plated steel sheet has been used in many cases. Pb-Sn is a material having extremely excellent weldability as used as a solder material. Even in resistance seam welding without using a wire electrode, the surface of the roller electrode is occasionally ground without much contamination of the roller electrode. Thus, no major problem occurred in the welding operation.

[0003] However, the problems of lead pollution during disposal of industrial waste and air pollution of lead, which is harmful due to corrosion by alcohol in a mixed fuel containing alcohol, have been highlighted worldwide. In recent years, Al has been free from such pollution problems.
Alternatively, a rust-preventive steel plate which has been coated with an Al-Si alloy or coated with a resin has been proposed.

[0004] One of the major problems in seam welding of an Al-based plated steel sheet is that during resistance welding, a brittle Al-Cu alloy layer is formed on the electrode surface due to the effect of the welding temperature and pressure on the electrode surface, resulting in poor current conduction. Becomes For this reason, it is necessary to always clean the electrode surface, and the Al—Cu alloy layer is removed by surface grinding. However, it is difficult to perform stable surface grinding, and in recent years, wire seam welding using a copper-based wire has recently been performed again. The law has attracted attention.

[0005] The wire electrodes used in seam welding generally have a larger cross-sectional shape in ordinary round bars in order for the contact surface between the wire and the roller electrode to obtain better current flow and less heating. I have.

[0006] The cross-sectional shape of a general wire electrode is V-shaped as shown in FIG. 4 (a) and FIG.
It has a U-shaped flat shape as shown in FIG. In the case of low-speed welding at a welding speed of about 2 to 4 m / min in seam welding, the guide groove 5 of the roller electrode 1 has a wire shape as shown in FIGS. 4 (a), 4 (b) and 4 (c) of the conventional example. There is little tendency for the wire electrode 2 to protrude and derail. But,
At high welding speeds of about 5 to 8 m / min, the wire electrode 2 tends to swing right and left with respect to the guide groove 5 of the roller electrode 1. When the wire electrode 2 swings, it is deformed on one side and has a uniform current density. Is difficult to obtain. Particularly, in the corner welded portion of the fuel tank 6, which is the work to be welded, the wire electrode tends to escape outward due to the direction of the frictional resistance.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and does not deform or derail one side of a wire electrode from a guide groove of a roller electrode during wire seam welding. At a corner weld of a fuel tank, the wire electrode tends to escape to the outside due to the direction of frictional resistance, so the wire electrode does not deform, derail or break, and the frictional force that overcomes this tendency is the guide groove of the roller electrode. It is another object of the present invention to provide a wire electrode having a cross-sectional shape such that a low frictional force and a stable current-carrying nugget can be obtained when the workpiece is turned at the time of welding the corner portion of the fuel tank.

[0008]

In order to achieve the above object, a seam welding electrode according to the present invention is a seam welding method in which a workpiece to be welded is pinched by a pair of opposed roller electrodes, and current is applied while rotating to weld. In the apparatus, a guide groove for a wire electrode having a substantially W-shaped cross-sectional shape disposed on the outer periphery of a pair of opposed roller electrodes, and a side contacting along the groove in a cross section of a back surface received in the groove. And a consumable wire electrode having a semicircular radius of curvature having a W-shaped cross-section on the opposite side in contact with the workpiece.

According to the present invention having the above structure, the wire electrode does not deform or derail on one side from the guide groove of the roller electrode during the wire seam welding, and the direction of the frictional resistance particularly at the corner welded portion of the fuel tank which is the work to be welded. The wire electrode tends to escape to the outside due to its properties, but the guide groove of the roller electrode has a frictional force that overcomes the above tendency, and also has low friction in turning the work piece when welding the corner of the fuel tank. It is possible to provide a wire electrode having a cross-sectional shape such that a current-driven nugget can be obtained stably with force.

According to still another feature of the present invention, the contact surface between the roller electrode guide groove disposed on the outer periphery of the pair of opposed roller electrodes and the consumable wire electrode received in the groove is W.
In combination with the cross-sectional shape of the roller electrode, the contact surface of the roller electrode guide groove and the consumable wire electrode received in the groove has 50 to 80% of the cross-sectional peripheral length of the wire electrode. In the guide groove, it is possible to prevent the tendency of the wire electrode to run around and the one-side deformation of the wire electrode caused by running around, and to prevent the wire electrode from derailing or breaking during high-speed welding at a welding speed of about 5 to 8 m / min. it can.

According to still another aspect of the present invention, a seam welding electrode comprising a roller electrode guide groove disposed on the outer periphery of a pair of opposed roller electrodes and a consumable wire electrode received in the groove. In the above, the wire cross-sectional shape of the consumable wire electrode in contact with the workpiece has a radius of curvature of 4 to 6 mmR, so that even when welding the corner of the fuel tank, which is the workpiece, A stable energized nugget with low frictional force for turning can be obtained.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a transverse sectional view showing a main part of a seam welding electrode according to the present invention, and FIG. 2 is a front view of the seam welding electrode.

FIG. 1A is a cross-sectional view of a main part of an embodiment of a seam welding electrode having a W-shaped cross section according to the present invention. (B) is a cross-sectional view of a main part of another embodiment of the seam welding electrode of the present invention in which the shape of the guide groove for the W-shaped roller electrode is changed, and (c) is a cross-sectional shape of the groove. This is still another embodiment in which a W-shape is connected horizontally. 1 is a roller electrode and 2 is a wire electrode. Reference numeral 3 denotes a guide groove for a W-shaped roller electrode, and the wire electrode 2 side contacting along the groove also has a W-shaped cross section. Reference numeral 4 denotes a guide groove for a roller electrode, which has a W-shaped cross-sectional shape. FIG. 2 is a front view of a pair of opposing roller electrodes, and FIG. 3 is a cross-sectional view of a main part of a seam welding electrode and an object to be welded. Reference numeral 6 denotes an object to be welded, and 1 and 2 use the same reference numerals as in FIG.

FIG. 5 to FIG. 8 are macrostructure diagrams of a welded section of an object to be welded by the seam welding electrode according to the present invention. 9 and 10 are microstructure diagrams on the left side of the welded portion, and FIGS. 11 and 12 are microstructure diagrams on the right side of the welded portion. 8 from 13.5 kA in FIG.
, A good nugget was obtained over a wide range up to 15.0 kA, which means that a good welding result could be stably obtained even if the welding current varied over a wide range.

From the above results, it has been proved that the electrode for seam welding of the present invention is superior to the electrode of the conventional example.

[0016]

As described above, according to the present invention, at the time of seam welding, the contact surface of the consumable wire electrode received in the groove with respect to the roller electrode guide groove has a W-shaped cross section. In combination, the contact surface between the roller electrode guide groove and the consumable wire electrode received in the groove has 50 to 80% of the cross-sectional peripheral length of the wire electrode.
In the guide groove of the roller electrode, it is possible to prevent the tendency of the wire to run around, the one-sided deformation of the wire caused by running around, and the derailment or disconnection of the wire electrode during high-speed welding at a welding speed of about 5 to 8 m / min. Further, the consumable wire electrode on the side that comes into contact with the workpiece has a wire cross section of 4 to 6 mm.
By having a radius of curvature of R, even in the welding of the corner portion of the fuel tank, which is the work to be welded, a low frictional force and a stable energized nugget can be obtained for the turning of the work to be welded at the time of welding. As a result of performing the welding while changing the welding current, a good nugget was obtained over a wide range from 13.5 kA to 15.0 kA. From this, a good welding result was obtained stably even at a high speed welding. This has the effect of contributing to an improvement in productivity during welding work.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a seam welding electrode having a W-shaped cross-sectional shape according to the present invention.

FIG. 2 is a front view of the electrode for seam welding of the present invention.

FIG. 3 is a cross-sectional view of a main part of an electrode for seam welding and an object to be welded.

FIG. 4 is a cross-sectional view of a main part of a conventional seam welding electrode.

FIG. 5 is a macrostructure diagram of a cross section of a welded portion of a workpiece to be welded at a welding current of 13.5 kA.

FIG. 6 is a cross-sectional macrostructure diagram of a welded portion of a workpiece to be welded at a welding current of 14.0 kA.

FIG. 7 is a macrostructure diagram of a welded section of a workpiece to be welded at a welding current of 14.5 kA.

FIG. 8 is a cross-sectional macrostructure diagram of a welded portion of a workpiece to be welded at a welding current of 15.0 kA.

FIG. 9 is a microstructure diagram of a weld cross section on the left side of the weld.

FIG. 10 is a microstructure view of a weld section on the left side of the weld section.

FIG. 11 is a microstructure diagram of a welded section on the right side of the welded part.

FIG. 12 is a sectional microstructure diagram of a weld portion on the right side of the weld portion.

[Description of sign]

 1, roller electrode 2, wire electrode 3, guide groove for W-shaped roller electrode 4, guide groove for roller electrode formed by connecting W-shape laterally, guide groove for roller electrode 6 of conventional example 6, workpiece 7, Energized nugget

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[Procedure amendment]

[Submission date] March 31, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG. 2

FIG. 3

FIG. 5

FIG.

FIG. 4

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

FIG. 11

FIG.

Claims (4)

[Claims] 1. A seam welding apparatus for clamping an object to be welded with a pair of opposed roller electrodes, energizing while rotating, and welding, wherein a substantially W-shaped cross-sectional shape provided on the outer periphery of the pair of opposed roller electrodes is provided. In a cross section of a wire electrode guide groove and a back surface received in the groove, a W-shape is formed on a side contacting along the groove, and a cross-sectional shape of a side contacting an object to be welded on the opposite side And a consumable wire electrode having a semicircular radius of curvature. 2. A contact surface of a roller electrode guide groove disposed on the outer periphery of a pair of opposed roller electrodes and a consumable wire electrode received in the groove has a cross-sectional peripheral length of 50 mm.
2. The electrode for seam welding according to claim 1, wherein the ratio is from 80% to 80%. 3. A seam welding electrode comprising a roller electrode guide groove disposed on the outer periphery of a pair of opposed roller electrodes and a consumable wire electrode received in the groove.
3. The electrode for seam welding according to claim 2, wherein the consumable wire electrode on the side in contact with the workpiece has a radius of curvature of 4 to 6 mmR. 4. A seam welding electrode comprising a roller electrode guide groove provided on the outer periphery of a pair of opposed roller electrodes and a consumable wire electrode received in the groove.
2. The consumable wire electrode according to claim 1, wherein the consumable wire electrode on the side in contact with the workpiece has a radius of curvature of 4 to 6 mmR.