JPH0970672A - Method for welding different metal plate body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and firmly perform a lap resistance welding of metal plate bodies having different qualities. SOLUTION: A through hole is formed on the face of a steel plate 1 having large electric resistance and high melting temperature, and brass plates 2A, 2B having small electric resistance and low melting temperature are lapped on both faces by inserting the steel plate 1 respectively. Respective energizing electrodes 3A, 3B are abutted with pressing onto the brass plates 2A, 2B from the outside respectively so as to cover the through forming range and welding current is supplied. The steel plate 1 is heated, the plate surface in contact therewith is melted, and intrudes into the through hole to be cooled, and solidified so as to form a bridge part 23 contenuousely between the upper and lower brass plates 2A, 2B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for resistance welding dissimilar plates such as brass and iron.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional example in which plate members are overlapped and resistance-welded.
The electrodes 3A and 3B at the tip of 4B are brought into pressure contact with each other, and a current is passed between the plates 5 and 6. Due to this welding current, resistance heating is generated at the contact portion between both plate bodies 5 and 6, and a nugget in which both plate bodies 5 and 6 are melt-solidified is formed to firmly bond the plate bodies.

[0003]

However, a plate body made of a material such as brass which has a low electric resistance and a low melting temperature of about 960 ° C., and a large electric resistance and a melting temperature of about 1500 ° C. Even if you try to weld a plate made of a material such as a high iron material by the above method, the brass plate is heated and softens and melts first due to the heat generated by the iron plate with high electrical resistance, and it is excessive due to the pressure applied to the electrode. Was likely to cause welding defects due to indentation or spatter.

Therefore, it is generally considered difficult to perform welding to realize a strong bond between dissimilar metals, and the metal atoms of both materials are mutually diffused at the joint interface by appropriate pressure and heating (200 ° C. to 450 ° C.). So-called diffusion bonding was the limit. However, the bond strength by this diffusion bonding is weaker than that by welding, and there is instability that is greatly affected by the degree of oxidation of the surface of the plate and the degree of contamination by oil.

In Japanese Unexamined Patent Publication (Kokai) No. 50-133947, when joining a cast iron plate and a steel plate, a through hole is provided in one plate body, and a metal slug is inserted in the through hole to form a metal plate. It has been shown that the resistance welding of the slag and the caulking deformation are continuously performed to realize a strong bond between different kinds of plate bodies. However, this method requires that the plate bodies have similar properties to some extent, and requires the labor of installing the metal slag as a separate member.

The present invention solves such a problem by providing different kinds of plates having different properties without trouble.
An object of the present invention is to provide a welding method capable of simply and firmly performing lap resistance welding.

[0007]

SUMMARY OF THE INVENTION A first feature of the present invention is that a first plate body (1) having at least one through hole (11) on the plate surface is sandwiched between the first plate body (1) and the first plate body (1). The second plate body (2A, 2) made of a material having a low electric resistance and a low melting temperature.
B) respectively, and then each electrode (3A,
3B) is pressed against the respective second plate bodies (2A, 2B) from the outside so as to cover the formation region of the through hole (11), and a welding current is caused to flow.

When a welding current is applied, the first electric resistance is large.
The plate body (1) generates heat, and the plate material of the second plate body (2A, 2B) melts at the plate surface portion in contact with the plate body (1) and enters the through hole (11) of the first plate body (1). When the welding current is stopped, the plate material that has entered the through hole (11) is cooled and solidified to form a bridge portion (23) continuous with the upper and lower second plate bodies. The upper and lower second plate bodies (2A, 2B) are integrated by this bridging portion (23), and the first plate body (1) is inserted from the upper and lower sides into the second plate bodies (2A, 2B).
The state of being crimped by B) is firmly bonded to each other.

Since the heat generated by the first plate body (1) hardly affects the plate surface of the second plate body (2A, 2B) which is not in contact with the first plate body, the plate surface is softened. Electrode (3A, 3
It does not cause excessive indentation of B). Second plate (2)
Is preferably formed by bending a single plate into a substantially U-shaped cross section, and forming the first plate body (1) by the opposing plate portions (21, 22).
Be sure to sandwich both sides of.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) In FIG. 1, three plate bodies 1, 2A and 2B are stacked, and these have a rectangular shape of the same shape in a plan view (FIG. 2). The central plate body 1 is made of a steel material having a high electric resistance and a high melting temperature, and a circular through hole 11 is formed at the center of the plate surface. In addition, the plate bodies 2A and 2B that are stacked on the upper and lower sides of the plate body 1 are
It is made of a brass material (for example, 7-3 brass) having a low electric resistance and a low melting temperature as compared with the above. In addition, as an example of the plate thickness of each plate, the steel plate 1 is 0.4 mm and the brass plate 2 is
A and 2B are 0.6 mm, and the diameter of the through hole 11 is φ1 m.
m. The plate width of these plate bodies 1, 2A, 2B is 4.0 mm.

Then, the cylindrical electrodes 3A and 3B provided at the tips of the welding arms 4A and 4B so as to further sandwich the brass plates 2A and 2B from above and below are the brass plates 2A and 2B, respectively.
Pressed against B. The outer diameter of each of the electrodes 3A, 3B is, for example, φ6 and larger than the diameter of the through hole 11 (FIG. 2), and these electrodes 3A, 3B face each other at symmetrical positions with the through hole 11 forming area of the steel plate 1 interposed therebetween. ing. The diameter of the through hole 11 is set to a size that does not exceed the diameters of the electrodes 3A and 3B and does not cause a decrease in strength of the steel plate 1.

The electrodes 3A and 3B are connected by a welding power source (not shown).
When welding current is passed between them (eg 6200A, 34m
s), brass plates 2A, 2B in contact with the steel plate 1 that generates heat by resistance
The temperature of the plate surface rises, this portion is melted, and the molten brass material enters the through hole 11. The molten brass material that has entered the through hole 11 rapidly cools and solidifies when the welding current is stopped, and the bridging portion 23 continuous to the upper and lower brass plates 2A and 2B.
(Fig. 3).

At this time, the brass plate 2 not in contact with the steel plate 1
The plate surfaces of A and 2B, that is, the plate surfaces on which the electrodes 4A and 4B are in pressure contact are not so affected by the resistance heat generation of the steel plate 1, so that excessive softening due to temperature rise does not occur.
It is possible to avoid the appearance of deep indentations that may damage the appearance. The upper and lower brass plates 2A, 2B are integrated by the formed bridging portion 23, and as a result, the steel plate 1 is a brass plate 2A,
2B is crimped from above and below to be firmly bonded to each other. In this case, the welding strength between the plate bodies 1, 2A, and 2B is sufficiently large as compared with the conventional diffusion bonding without causing breakage in the welded portion even when a shear load of 30 to 35 kg is applied.

(Second Embodiment) As shown in FIG. 4, a brass plate 2 is formed by bending a single plate into a substantially U-shape and sandwiching the steel plate 1 between the plate parts 21 and 22 facing each other. Even if so, the same effect as that of the first embodiment can be obtained. (Other Embodiments) The combination of plates is not limited to the steel material and the brass material as in the above embodiments, one of which has a high electric resistance and a high melting temperature, and the other of which has a low electric resistance and The present invention can be widely applied to different kinds of plates made of materials having a low melting temperature.

Further, the number of the through holes is not limited to one, and a plurality of through holes may be provided in order to improve the welding strength within a range in which the strength of the base material such as a steel plate does not decrease. In addition, as a control method of the welding power source, it is preferable to use the inverter control which is excellent in heat concentration efficiency on the welded portion, but other methods such as an AC type, a DC type and a condenser type may be used.

The shape of the through hole is not limited to the circular shape.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of plates to be lap-welded according to a first embodiment of the present invention.

FIG. 2 is a plan view of a plate body to be lap-welded according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part of a plate body to be lap-welded according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of plates to be lap-welded according to the second embodiment of the present invention.

FIG. 5 is a sectional view of a plate body to be lap-welded according to a conventional example.

[Explanation of symbols]

1 ... Steel plate, 11 ... Through hole, 2, 2A, 2B ... Brass plate,
21, 22 ... Plate part, 23 ... Bridge part, 3A, 3B ... Electrode.

Claims (3)

[Claims] 1. At least one through hole (11) in the plate surface.
On both sides of the first plate body (1) having an electric resistance smaller than that of the first plate body (1) and a melting temperature of the first plate body (1).
The step of stacking the second plate bodies (2A, 2B) made of a material lower than the plate body, and the electrodes (3A, 3B) for energization, the through holes (11)
So as to cover the formation area of each of the second plate members (2
A, 2B) are pressed against each other from the outside to flow a welding current, and a part of each of the second plate bodies (2A, 2B) is melted and introduced into the through hole (11). Welding method for dissimilar plates. 2. A second plate body (2) formed by bending a single plate into a substantially U-shaped cross section, and facing plate portions (21, 22).
The welding method for different types of plate bodies according to claim 1, wherein both surfaces of the first plate body (1) are sandwiched by the above. 3. At least one through hole (11) in the plate surface.
And a first plate body (1) having an electric resistance smaller than that of the first plate body (1) and a melting temperature of the first plate body (1) sandwiching the first plate body (1). A second plate body (2A, 2B) made of a material lower than the plate body (1), and a part of each of the second plate bodies (2A, 2B) is provided with the through hole (1
1) A welded structure for a dissimilar plate body, comprising: a cross-linking portion (23) formed by melting and entering into the inside.