JPH0655278A - Electric resistance welding method for different kinds of materials - Google Patents

Abstract

PURPOSE:To weld a panel inner and an impact bar with different electric conductivity in a perfect state via clad materials. CONSTITUTION:The same kind of materials of clad materials 2 of a steel plate 2a and an aluminum plate 2b are interposed in opposition between a flange part 1a of the panel inner 1 made of steel material and a flange part 3a of the impact bar 3 made of aluminum material, energizing between both electrodes 4 and 5 is controlled at two steps in this state, first, the flange part 1a of the panel inner 1 and the steel plate 2a of the clad materials 2 and then, the flange part 3a of the impact bar 3 and the aluminum plate 2b of the clad materials 2 are subjected to resistance welding in order. Consequently, high electric conductivity materials of the flange part 1a and the steel plate 2a and low electric conductivity materials of the flange part 3a and the aluminum plate 2b can be subjected to resistance welding in a satisfactory state, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of electrically resistance-welding different kinds of materials by passing an electric current between two kinds of different kinds of materials having a high conductivity and a low conductivity. The present invention relates to an electric resistance welding method for materials.

[0002]

2. Description of the Related Art Conventionally, it has been very difficult to electrically resistance-weld two dissimilar materials having different electric conductivities due to the setting of the welding current. That is, when resistance-welding a high-conductivity material that can be welded with only a small current and a low-conductivity material that requires a large current at the time of welding, if a small current is passed, the welding current for the low-conductivity material is Run short. For this reason, the low-conductivity material is not completely melted, and as a result, insufficient penetration of the high-conductivity material and the low-conductivity material occurs.

On the other hand, when a large current is applied, the low-conductivity material can be sufficiently melted, but on the other hand, the welding current for the high-conductivity material becomes excessive.
Therefore, defective phenomena such as dust generation and thermal strain occur on the high-conductivity material side.

Therefore, in recent years, Japanese Laid-Open Patent Application No. 3-29407 has been used.
A welding method of different kinds of materials as disclosed in Japanese Patent No. 1 has been proposed. In this welding method, by interposing an intermediate conductive material between the high conductive material and the low conductive material, the difference in conductivity between the materials to be welded is relaxed and the It is designed to perform resistance welding.

[0005]

However, in the welding method in which an intermediate conductive material is interposed between the high conductive material and the low conductive material as in the above-mentioned conventional method, the high conductive material and the low conductive material are not used. Compared to direct resistance welding of different materials, the difference in conductivity between different materials is reduced and a relatively good welding state can be obtained, but resistance welding of different materials in a completely good state You cannot do it. Further, when there is a very large difference in conductivity between the high-conductivity material and the low-conductivity material, it is possible to reduce the difference in conductivity between the respective materials even if an intermediate conductive material is interposed. However, there is a problem that incomplete welding or defective phenomenon is caused as a result.

[0006]

In order to solve the above-mentioned problems, the method for electric resistance welding of dissimilar materials according to the present invention applies an electric current between two dissimilar materials having different electric conductivities so that the dissimilar materials are connected to each other. The following measures are taken in the electric resistance welding method for dissimilar materials in which electric resistance welding is performed.

That is, a laminated material in which the high conductivity material and the low conductivity material forming the different materials are pressure-bonded to each other is interposed between the different materials so that the same materials face each other. First, a small current for resistance welding the high-conductivity materials is applied, and then a large current for resistance welding the low-conductivity materials is applied.

[0008]

According to the electric resistance welding method for different materials described above, one of the highly conductive materials forming the different materials and the highly conductive material of the laminated material are resistance-welded with a small current, and then such high conductivity is obtained. In the welded state of the materials, the other low-conductivity material which is a different material and the low-conductivity material of the laminated material are resistance-welded by a large current. As a result, high-conductivity materials and low-conductivity materials can be resistance-welded in good condition, and as a result, two dissimilar materials with different conductivity can be welded in perfect condition through the laminated material. You can

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS. In the following description, the case where the electric resistance welding method for different kinds of materials is applied to spot welding of automobile doors is illustrated.

In the automobile door according to this embodiment, as shown in FIG. 1, the front and rear end flange portions 1a of the panel inner 1 (only the front end is shown in the figure) are provided with a clad material 2 as a laminated material. Via the front end and the rear end flange portion 3a of the impact bar 3, and the impact bar 3 described above is welded to the panel inner 1 as well.
It is formed by welding to a panel outer (not shown) through the clad material 2.

The panel inner 1 is made of a steel material having high conductivity (highly conductive material) as a raw material, and enables welding between similar materials with a relatively small current value of about 10,000 A. ing. On the other hand, the impact bar 3 uses an aluminum material (low conductivity material) having a low conductivity as a raw material, and the current value required for welding between similar materials is 3 to
It is relatively large at around 40,000 A. The impact bar 3 is provided to prevent the door from being deformed in the event of a collision, and is made of an aluminum material different from the steel material of the panel inner 1 in order to reduce the weight of the automobile door.

The clad material 2 is formed by pressing a steel plate 2a of the same kind as the raw material of the panel inner 1 and an aluminum plate 2b of the same kind as the raw material of the impact bar 3 with a rolling roller. There is. Incidentally, such a contact surface between the steel plate 2a and the aluminum plate 2b is mechanically bonded as a whole, and even in the electrical resistance welding described later, there is no problem in the crimping state. It's not something you can do.

Next, the clad material 2 of the panel inner 1 and the impact bar 3 made of different materials as described above.
The electrical resistance welding via the will be described below with reference to FIGS. 2 to 6. The energizing current between both electrodes 4 and 5, which will be described later, is controlled by a controller (not shown) for the time shown in FIG. The current I _S is supplied, and then the large current I _{A of} about 30 to 40,000 _A is supplied.

First, as shown in FIG. 3, the steel plate 2a
With the aluminum plate 2b facing the impact bar 3 and the clad material 2 with the flange portion 1a of the panel inner 1 and the impact bar 3 facing each other.
And the flange portion 3a. Then, with such a clad material 2 interposed, the flange portion 1a of the panel inner 1 and the flange portion 3a of the impact bar 3 are sandwiched between the upper and lower spot electrodes 4 and 5 and clamped with a predetermined pressing force. While energizing between both electrodes 4 and 5.

At this time, the current flowing between the electrodes 4 and 5 is a small current I _S of about 10,000 A shown in FIG. As a result, the panel inner 1 made of the same kind of steel material
The flange portion 1a and the steel plate 2a of the clad material 2 are resistance-welded to each other as shown in FIG. By the way, the small current I flowing between both electrodes 4 and 5 as described above.
_S is a current value sufficient for resistance welding of a highly conductive steel material. Therefore, the flange portion 3a of the impact bar 3 made of the same kind of aluminum material and the aluminum plate 2b of the clad material 2 have not yet been resistance-welded at this point.

Next, as shown in FIG. 5, in the welded state of the flange portion 1a of the panel inner 1 and the steel plate 2a of the clad material 2, a large current I _{A is} passed between the electrodes 4 and 5.
As a result, the impact bar 3 made of the same kind of aluminum material
The flange portion 3a and the aluminum plate 2b of the clad material 2 are resistance-welded to each other as shown in FIG. As a result, dissimilar materials of the panel inner 1 made of steel material and the impact bar 3 made of aluminum material are electrically resistance welded through the clad material 2 of the steel plate 2a and the aluminum plate 2b.

The large current I _A between the electrodes 4 and 5 for resistance welding the flange portion 3a of the impact bar 3 and the aluminum plate 2b of the clad material 2 as described above is due to the flange portion 1a of the panel inner 1. An excessive current is applied to the resistance welding between the steel plate 2a and the clad material 2.

However, since the flange portion 1a of the panel inner 1 and the steel plate 2a of the clad material 2 are already resistance welded by the small current I _S and are in a good conductive state, they are damaged by the large current I _A. There is no. Therefore, by controlling the energizing current between both electrodes 4 and 5 with respect to time as described above, the panel inner 1 and the impact bar 3 via the clad material 2 are firmly welded under appropriate conditions. It will be possible.

The above embodiment is not intended to limit the present invention, and various modifications can be made within the scope of the present invention.
For example, in the above embodiment, the steel material of the panel inner 1 and the aluminum material of the impact bar 3 are exemplified as different materials, but the materials are not particularly limited to such materials. When a material other than steel or aluminum is used, the current flowing between the electrodes 4 and 5 is set to each current value corresponding to resistance welding.

[0020]

The electrical resistance welding method for dissimilar materials according to the present invention comprises:
As described above, a laminated material in which high-conductivity and low-conductivity materials forming different materials are pressure-bonded to each other is interposed between the different materials, with the same materials facing each other. First, a small current for resistance welding high conductivity materials is applied, and then a large current for resistance welding low conductivity materials is applied.

Thus, unlike a conventional welding method in which an intermediate conductive material is interposed between different kinds of materials so as to reduce the difference in conductivity, a laminated structure corresponding to different kinds of high and low conductive materials is formed. By interposing the material, the electrical conductivity of each material to be resistance-welded can be made equal. Then, by controlling the welding current in two stages in such an intervening state of the laminated material, it is possible to perform resistance welding of the high conductive material and the low conductive material in a good state, and as a result, the conductive Two dissimilar materials having different rates can be welded together in perfect condition through the laminated material.

In the welding method with the laminated material interposed as described above, the high and low conductive materials forming the laminated material are made to correspond to different materials so that the conductivity difference between the different materials is not affected. It has the effect of enabling complete resistance welding of dissimilar materials.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a panel inner, an impact bar, and a clad material that constitute an automobile door according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the value of the current passed between the panel inner and the impact bar and time.

FIG. 3 is a vertical cross-sectional view showing a state in which a small current is applied between the inner panel and the impact bar.

FIG. 4 is a vertical cross-sectional view showing a state in which the flange portion of the panel inner and the steel plate of the clad material are resistance-welded.

FIG. 5 is a vertical cross-sectional view showing a state in which a large current is passed between the inner panel and the impact bar.

FIG. 6 is a vertical cross-sectional view showing a state in which the flange portion of the impact bar and the aluminum plate of the clad material are resistance-welded.

[Explanation of symbols] 1 panel inner (highly conductive material) 2 clad material (laminated material) 3 impact bar (low conductive material) I _S small current I _A large current

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Nohisa Miwa 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Mitsugu Fukahori 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. Within

Claims (1)

[Claims] 1. An electric resistance welding method for dissimilar materials in which an electric current is passed between two dissimilar materials having different electrical conductivity, and the dissimilar materials are electrically resistance-welded to each other. Laminated materials in which conductive materials are mutually pressure-bonded are interposed between different kinds of materials with the same kind of materials facing each other. A method for electrical resistance welding of dissimilar materials, characterized by flowing a large current for resistance welding of low-conductivity materials.