JPH08332576A - Resistance welding method for hollow section metal members - Google Patents

Abstract

(57) [Summary] [Object] To provide a resistance welding method capable of obtaining a desired welding strength without deforming a welding member even at a low current. A first metal member 1 having a hollow cross-section and a second metal member 2 having at least two plate-shaped portions 2a, 2a.
And electrodes 3 and 3 for resistance welding, and a third metal member 4 having a higher electric conductivity than the second metal member 2 are prepared.
The third metal member 4 is inserted into the hollow cross section 1a of the first metal member 1 so as to interpose the third metal member 4 on the line connecting the electrode 3 and the electrode 3, and the first metal member 1 is inserted. The second metal member 2 is sandwiched between the plate-shaped portions 2a, 2a, and these plate-shaped portions 2a, 2a
A is pressurized and energized by the electrodes 3 and 3. [Effect] The welding current easily flows through the third metal member, and the strength of the welded portion between the first and second metal members can be increased. That is, a low welding current is required to obtain the required welding strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding technique for hollow section metal members.

[0002]

2. Description of the Related Art There is a method of using a joint for joining metal members having a hollow cross-sectional structure, but the number of parts increases and the cost increases. There is also an arc welding method using butting, but the thermal strain is large. As one method for improving this, there is a resistance welding method in which a plate-shaped portion is provided at a joint portion of a hollow cross-section member and series welding is performed on two surfaces sandwiching the other member.

FIG. 4 is an explanatory view of a conventional resistance welding method for a hollow cross-section member, which is a first metal member 100 having a hollow cross-section structure.
And a second metal member 102 having two plate-shaped portions 101, 101 and resistance welding electrodes 103, 103 are prepared.
The first metal member 100 is sandwiched between the plate-like portions 101, 101 of the second metal member 102, and these plate-like portions 101, 1
01 is energized under pressure by the electrodes 103, 103. As a result,
Nuggets 104, 104 are formed on the contact surface between the first and second metal members 100, 102.

[0004]

The current flowing between the electrodes 103 and 103 causes the current path C1 to flow through the first metal member 100.
Current i1 and the second metal member 102 through the current path C
The current i2 is 2. As is clear from the figure,
The current i1 is a current effective for welding, and the current i2 is a current invalid for welding.

Due to this shunt, the current i1 that contributes to welding
Of the nugget may not be formed and the welding strength may be reduced. Here, in order to obtain a desired welding strength, there is a method of increasing the current value between the electrodes, but the cost becomes a problem. An object of the present invention is to provide a resistance welding method capable of obtaining a desired welding strength without deforming a welding member even at a low current.

[0006]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, a first metal member having a hollow cross section and a second metal member having at least two plate-shaped portions are provided. An electrode for resistance welding and a third metal member having a higher electrical conductivity than the second metal member are prepared, and the third metal member is provided on the line connecting the electrodes. It is characterized in that the third metal member is inserted into the first metal member, the first metal member is sandwiched by the plate-shaped portions, and the plate-shaped portions are pressurized and energized by the electrodes.

In the second aspect, the first metal member and the second metal member are aluminum-based materials, and the third metal member is a copper-based material.

In the third aspect, the second metal member is a hollow cross-section metal member.

[0009]

According to the present invention, by inserting the third metal member, which is a high electric conductivity member, into the hollow cross section of the first metal member, a large amount of welding current flows through the high electric conductivity member.

In the second aspect, the third metal member, which is a copper-based material, is more likely to flow a welding current than the first and second metal members, which are an aluminum-based material.

In the third aspect, the second metal member is a metal member having a hollow cross section, which facilitates formation of a plate-like portion for connection.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a specific example of the resistance welding method according to the present invention. To perform resistance welding, first, a first metal member 1 having a hollow cross section 1a, two plate-shaped portions 2a,
Second metal member 2 having 2a and electrodes 3 and 3 for resistance welding
And a third metal member 4 having a higher electrical conductivity than the second metal member 2 are prepared. The third metal member 4 is a member having a higher electric conductivity than the second metal member 2, that is, a member having a high electric conductivity.

Next, the third metal member 4, which is a highly electrically conductive material, is inserted into the hollow cross section 1a of the portion where the first metal member 1 is welded. After that, the portion of the first metal member 1 to be welded is sandwiched between the plate-like portions 2a and 2a of the second metal member 2, and these plate-like portions 2a and 2a are sandwiched between the electrodes 3 and 3 and added. Press.

FIG. 2 is a side view showing a specific example of the resistance welding method according to the present invention. The third metal member 4 which is a highly electrically conductive material is placed on a straight line CL connecting the centers of the electrodes 3, 3. Is installed. It is not necessary to align the center of the third metal member 4 on this line, and it is sufficient if the member 4 is on this line even if it is slightly displaced as shown by the chain line.

FIG. 3 is a diagram showing the operation of the resistance welding method according to the present invention. When energized, a current path C0 is passed through the third metal member 4, a current path C1 is passed through the first metal member 1, and a second metal path is run. A current path C2 is formed in the member 2, and a current i0 is generated in the path C0.
A current i1 flows through the path C1 and a current i2 flows through the path C2. As a result, nuggets 5 and 5 are formed on the contact surface between the first and second metal members 1 and 2.

The measurement result of the current shunt by the current path of the method of the present invention will be described based on Table 1. In addition, in FIG.
The first metal member 1 has a thickness of 3 mm and 40 mm square, and the second metal member 2 has a thickness of 2 mm and 44 mm square.
IS-6061-T5 (Al-Mg-Si based aluminum alloy) extruded material, the third metal member 4 is 30 mm square pure copper, the electrodes 3 and 3 are 16 mm in diameter, and the radius of the tip is 8
It is a 0 mm oxygen-free copper electrode.

[0017]

[Table 1]

Example 1 and Comparative Example 1: In Example 1 and Comparative Example 1, the welding current was 26 kA, the energizing time was 10 cycles, and the pressing force was 300 kgf.

Example 1 Under the condition that copper is used as the high electric conductive member, a current path C0 formed in this copper (see FIG. 3).
(See also) and the current i1 of the current path C1 formed in the aluminum member that is the first metal member is 12.8 kA, and this current is 12.8 kA. It flows through the contact surfaces between and is used for welding. The reactive current i2 flowing through the current path C2 is 13.0 kA.
In this example, the current effective for welding was about 1.5 times that of the comparative example 1, and the effect of inserting the highly electrically conductive member was sufficiently exhibited.

Comparative Example 1: When the current value of each current path was measured under the condition that there was no high electric conductive member, the current i1 effective for welding flowing in the current path C1 (see also FIG. 4) was 8.6 k.
A, the current i2 that is ineffective in welding and flows in the current path C2 is 1
The current i1 that is 7.1 kA and is effective for welding is only 1/3 of the total current.

Next, the result of nugget formation by the method of the present invention will be described based on Table 2. The dimensions and materials of the components of this experiment are the same as those shown in FIG. This experiment was performed with an insert material interposed between the two metal members 1 and 2. The insert material is 35 wt% epoxy resin + 6.5 wt% MnO ₂ + 42.25 wt%
Magnesium + 16.25% by weight aluminum,
This insert amount is 0.3 g / 900 mm ² .

[0022]

[Table 2]

Example 2 and Comparative Example 2: In Example 2 and Comparative Example 2, the welding current was 40 kA, the energization time was 10 cycles, and the pressing force was 300 kgf.

Example 2: Under the condition that copper was used as the high electric conductive member, the nugget diameter was 6.2 mm at the upper part of FIG.
It was 5.8 mm at the bottom. The nugget diameter of this example is about twice as large as that of Comparative Example 2 described later, and the welding strength is significantly increased. In other words, low current is required to obtain the required welding strength.

Comparative Example 2: Under the condition that there is no high electric conductive member, the nugget diameter is 2.5 mm in the upper part of FIG. 1 and 3.
It became 1 mm.

The high electrical conductivity member 4 of the above embodiment is effective not only for improving the current amount at the welded portion, but also for preventing the bending of the member having the hollow cross section structure due to the pressure applied by the electrode. To do. Further, in the insert materials used in the above-mentioned examples, the MnO ₂ powder and the Mg and Al powders undergo a thermite reaction during welding, and the nugget is expanded and the welding strength is increased by the reaction heat. Then, the eutectic reaction of Mg and Al lowers the melting point of the nugget portion and enables welding at low current.

[0027]

The present invention has the following effects due to the above configuration. The resistance welding method according to claim 1, wherein the first method has a hollow cross section.
A metal member, a second metal member having at least two plate-shaped portions, a resistance welding electrode, and a third metal member having a higher electric conductivity than the second metal member, The third metal member is provided on the line connecting the electrode so that the third metal member is interposed.
The first metal member is inserted into the first metal member, the first metal member is sandwiched by the plate-like portions of the second metal member, and the plate-like portions are energized under pressure by the electrodes, so that the welding current is It becomes easier to flow through the third metal member and the weld strength between the first and second metal members can be increased. That is, a low welding current is required to obtain the required welding strength.

In the resistance welding method of the second aspect, the first metal member and the second metal member are aluminum-based materials, and the third metal member is the aluminum-based material.
Since the metal member of 1 is a copper-based material, the resistance of copper is smaller than that of aluminum, so that the welding current easily flows through the third metal member.

In the resistance welding method according to the third aspect, since the second metal member is the hollow cross-section metal member, the plate-shaped portion can be easily formed, and the number of steps for welding the hollow cross-section members can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a specific example of a resistance welding method according to the present invention.

FIG. 2 is a side view showing a specific example of the resistance welding method according to the present invention.

FIG. 3 is a diagram showing the operation of the resistance welding method according to the present invention.

FIG. 4 is an explanatory view of a conventional resistance welding method for a hollow cross-section member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st metal member, 1a ... Hollow cross section, 2 ... 2nd metal member, 2a ... Plate part, 3 ... Electrode, 4 ... 3rd metal member,
5 ... Nugget, C0, C1, C2 ... Current path.

Claims (3)

[Claims] 1. A first metal member having a hollow cross-sectional structure, a second metal member having at least two plate-like portions, a resistance welding electrode, and a higher electric conductivity than the second metal member. A third metal member is prepared, and the third metal member is inserted into the hollow cross section of the first metal member so as to interpose the third metal member on the line connecting the electrodes. A resistance welding method for a hollow cross-section metal member, characterized in that the first metal member is sandwiched between the plate-shaped portions of the second metal member, and these plate-shaped portions are pressurized and energized by the electrodes. 2. The hollow cross section according to claim 1, wherein the first metal member and the second metal member are aluminum-based materials, and the third metal member is a copper-based material. Resistance welding method for metal members. 3. The resistance welding method for a hollow cross-section metal member according to claim 1, wherein the second metal member is a hollow cross-section metal member.