JPH05329626A - Method for joining aluminum material - Google Patents

Abstract

PURPOSE:To well join two aluminum materials without using a flux by interposing an Al-Ai brazing filler metal between the joint surfaces of both aluminum materials and pressurizing the materials under the specific pressurizing force and further applying ultrasonic vibrations to the one aluminum material. CONSTITUTION:The joint surfaces of the two aluminum materials A1, A2 are pressurized under <=0.01 to 20kgf/mm<2> pressurizing force via a pressurizing lever 5 by a weight 8 for loading in a direction where the joint surfaces are pressed to each other. The ultrasonic vibrations in a vertical direction oscillated from an ultrasonic vibrator transducer are simultaneously imparted to the aluminum material A2 on the left side by a horn 9. Consequently, the oxide films on the joint surfaces of the two aluminum materials are broken by the ultrasonic waves and the friction heat is generated between the two aluminum materials and the brazing filler metal 11. The brazing filler metal is then melted and the molten metal arrives at the base of the joint surfaces. The two aluminum materials are thus joined. Then, there is no need for separately providing heating means and energy for melting the brazing filler metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining aluminum materials, which is applied to join aluminum materials in manufacturing aluminum automobile parts, aluminum heat exchangers and the like.

In this specification, the term "aluminum" includes aluminum alloy in addition to pure aluminum.

[0003]

2. Description of the Related Art Conventionally, aluminum materials are joined by supplying a brazing material to the joining portion and removing an oxide film formed on the joining surface of the aluminum material and the surface of the brazing material. For this purpose, a suspension of flux is applied to the brazing part and heated to perform brazing. However, since it is necessary to supply the brazing filler metal and apply the flux suspension in separate operations, there is a problem that the operations are troublesome. Moreover, since the amount of flux applied varies, stable brazing cannot be performed, and when the amount of flux suspension becomes large, it may drip and stain the brazing furnace. It was Also, when using a chloride-based flux,
Since the aluminum product after brazing corrodes due to the residue of the flux, the flux must be cleaned after the brazing, which is troublesome and costly. Further, since a heating means for melting the brazing material is required and its energy is required, this also raises a problem that the cost becomes high.

As a joining method which does not require the flux as described above, there is known an ultrasonic soldering method in which soldering is performed while removing an oxide film on the joining surface by using ultrasonic waves. There are generally two ultrasonic soldering methods, the first of which is
The aluminum material to be joined is immersed in the molten solder contained in the treatment tank, and ultrasonic vibration is applied to the molten solder using the ultrasonic vibrator attached to the treatment tank to form an oxide film on the joint surface. This is a method of soldering while destroying.

However, this method has a problem that the equipment becomes large-scaled, a large amount of solder is required, and the wall of the processing tank is corroded by ultrasonic waves, resulting in high cost. Further, in the lap joint portion, the anti-shrink joint portion, and the butt joint portion having a small clearance, there is a problem that the oxide film is not sufficiently destroyed and a joint failure occurs. In order to solve this problem, it is necessary to increase the clearance of the joint, but this does not provide sufficient dimensional accuracy of the product obtained, and in some cases there is a problem that the aluminum materials will be displaced during the joining process. ..

The second ultrasonic soldering method is a soldering method using a soldering iron to which an ultrasonic vibrator is attached.

However, this method has a problem that the life of the tip of the soldering iron is short and the cost is high.

An object of the present invention is to provide a method for joining aluminum materials which solves the above problems.

[0009]

According to the method for joining aluminum materials of the present invention, an Al-Si type brazing material is interposed between the joining surfaces of two aluminum materials, and both aluminum materials are 0.01 to 20 kgf / mm ^2. By applying pressure in the direction of pressing the joint surfaces with each other, and applying ultrasonic vibration to at least one of the aluminum materials, the oxide film on the joint surface of both aluminum materials and the oxide film on the brazing material surface are destroyed. In addition, frictional heat is generated between the aluminum material and the brazing material, and the brazing material is melted by the generated frictional heat to braze both aluminum materials.

In the above description, the pressing force applied to press the two aluminum materials is limited to the range of 0.01 to 20 kgf / mm ^{2 because} when the pressing force is smaller than the lower limit value, the aluminum material is This is because slippage occurs between the holding portion and the ultrasonic wave transmission becomes insufficient, and if the upper limit is exceeded, buckling or deformation of the aluminum material may occur.

The ultrasonic vibration applied has a frequency of 10 to 20.
kHz, amplitude 5 to 100 μm, output 100 to 4500 W
It is good to say Also, the application time of ultrasonic vibration is 1.0
~ 5.0 seconds is recommended. This is because within such a range, the oxide film is sufficiently destroyed and the brazing material is sufficiently melted. In addition, ultrasonic vibrations
It is preferable to apply it in a direction parallel to the joining surface of the aluminum material.

The surface roughness of the joining surface of the aluminum material is preferably in the range of 0.5 to 50 μm. The reason is that if it is within this range, frictional heat is most likely to be generated most efficiently, and processing for making it within this range can be easily performed.

As the Al-Si-based brazing material, it is possible to use all those used for brazing of aluminum materials by a usual method, for example, Si 3 to 12% by weight.
Including the balance of inevitable impurities and Al,
What added the required component to this in order to obtain desired performance is used. The thickness of the brazing material is 0.05 to 0.5 mm
It is preferably within the range. The reason is 0.05
It is difficult to make the thickness less than mm, and it is 0.5
This is because if it exceeds mm, the bonding strength and the elongation are reduced.

[0014]

According to the method of the present invention, both aluminum materials are pressed with a pressure of 0.01 to 20 kgf / mm ^{2 in} the direction in which the joint surfaces are pressed against each other, and ultrasonic vibration is applied to at least one of the aluminum materials. Since the oxide film on the joint surface of both aluminum materials and the oxide film on the surface of the brazing material are destroyed by applying the flux, flux for removing such oxide film is not required. further,
By applying ultrasonic vibration, frictional heat is generated between the aluminum material and the brazing material, and the brazing material is melted by this frictional heat to braze both aluminum materials. It does not require separate means and energy. Moreover, since the molten brazing material flows between the destroyed oxide films and reaches the base material of the joint surface, it becomes possible to favorably join both aluminum materials.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an apparatus used for joining round bar-shaped aluminum materials with a butt joint according to the method of the present invention. In the following description, FIG.
The left and right of is called left and right.

In FIG. 1, the ultrasonic bonding apparatus is a base.
The fixed base (2) fixedly mounted on (1) and the holder (3) mounted on the fixed base (2) so as to be movable in the left-right direction and holding one round bar-shaped aluminum material (A1). I have it. On the right side of the holder (3), a bracket (4) protruding upward is fixedly provided on the fixing base (2), and the bracket (4) has an upper end facing in a direction orthogonal to the left-right direction. A pressure lever (5) is mounted that is rotatable around a horizontal axis. The upper end of the weight suspension member (7) is pivotally attached to the right end of the holder (3). The weight suspension member (7) has a weight
(8) is designed to be detachable,
By changing the weight of (8), the pressure applied to the joining surfaces of the two aluminum materials (A1) and (A2) described later is changed.

On the left side of the fixed base (2), a horn (9) for increasing the vibration speed of ultrasonic waves transmitted by an ultrasonic vibrator (not shown) is arranged at a distance from the fixed base. At the lower end of the horn (9), hold the other aluminum material (A2)
0) is provided, and the holding portion (10) holds the other aluminum material (A2) so as to be on the same axis as the one aluminum material (A1). Both aluminum materials (A1)
A brazing material (11) is interposed between the joint surfaces at the tip of (A2).

In such a construction, in order to join both aluminum materials (A1) and (A2), the load weight (8)
0.01 to 20k in the direction to press the joining surfaces of both aluminum materials (A1) and (A2) against each other via the pressure lever (5).
While pressing with a pressure of gf / mm ² or less, the ultrasonic vibration in the vertical direction transmitted from the ultrasonic vibrator is
It is applied to the left aluminum material (A2) by (9). Then, ultrasonic waves destroy the oxide film on the joint surface of both aluminum materials (A1) and (A2), and
1) Friction heat is generated between (A2) and the brazing filler metal (11), the brazing filler metal (11) is melted by the generated friction heat, and the molten brazing filler metal (11)
Reaches the base material of the joint surface between the destroyed oxide films, and as a result, both aluminum materials (A1) and (A2) are well joined.

Hereinafter, more specific examples of the method of the present invention will be described together with comparative examples.

Concrete Example 1 This concrete example was carried out using the apparatus shown in FIG. Diameter 5mm, length 30mm and diameter 5m
Prepare two round rod-shaped aluminum materials (A1) and (A2) made of JIS A1050 with a length of 50 mm and a length of 50 mm, and then apply Emery polishing treatment or buff polishing treatment to one of the joint surfaces, and then use acetone. Was used for ultrasonic cleaning. The center line surface roughness of the joint surface is 19 μm. Also, brazing material
As (11), a diameter of 5 mm made of Al-10 wt% Si,
A disk-shaped product having a thickness of 0.2 mm was prepared. Then, the first aluminum material (A1) is held in the holder (3) and the second aluminum material (A2) is held in the holding portion (10) of the horn (9), and both aluminum materials (A1) (A2) are held. A brazing filler metal (11) was interposed between the joint surfaces of.

In this state, the load weight (8) applies a pressure of 10 MPa in the direction in which the joining surfaces of the aluminum materials (A1) and (A2) are pressed against each other via the pressing lever (5). did. At the same time, the ultrasonic vibration in the vertical direction transmitted from the ultrasonic vibrator was applied to the aluminum material (A2) on the left side for 5.0 seconds by the horn (9). The output of ultrasonic waves was 4500 W, the frequency was 20 kHz, and the amplitude was 25 μm. In this way, both aluminum materials (A1) and (A2) were joined.

Concrete Example 2 Two aluminum materials (A1) and (A2) were joined in the same manner as in Concrete Example 1 except that the applied pressure was 50 MPa.

Concrete Example 3 Two aluminum materials (A1) and (A2) were joined in the same manner as in Concrete Example 1 except that the applied pressure was 100 MPa.

Comparative Example 1 Two aluminum materials (A1) and (A2) were bonded in the same manner as in the above-described specific example 1 except that the pressure was 0.5 MPa.

Comparative Example 2 Two aluminum materials (A1) and (A2) were bonded in the same manner as in the above-described specific example 1 except that the pressure was 300 MPa.

Evaluation Test When a tensile test was performed on the joined products obtained in the concrete examples 1 to 3, the joints did not break, and so-called base metal fracture occurred in the aluminum material. On the other hand, the bonded product obtained in Comparative Example 1 hardly bonded. Further, in the joined product obtained in Comparative Example 2, the joint portion of the aluminum material was melted and cracks were generated in this portion.

[0028]

According to the method of joining aluminum materials of the present invention, as described above, without using a flux,
Since aluminum materials can be joined well, there is no need to supply flux or clean flux residue as in the conventional brazing method, resulting in easier work and higher productivity. The cost will be cheaper as it improves. Further, unlike the conventional brazing method, since heating means and energy for melting the brazing material are not required, the equipment is simplified and the cost is reduced.

Further, unlike the first ultrasonic bonding method of the related art, large equipment and a large amount of solder are not required, and the ultrasonic waves are applied only to the aluminum material, so that the device is destroyed. There is no fear. Therefore, the cost is lower than that of the conventional method. Further, unlike the second ultrasonic brazing method of the related art, since a chip having a short life is not required, the cost is lower than that of the conventional method.

[Brief description of drawings]

FIG. 1 is a view showing an apparatus used for joining round bar-shaped aluminum materials with a butt joint according to the method of the present invention.

[Explanation of symbols]

 11 Brazing material A1 Aluminum material A2 Aluminum material

Claims (1)

[Claims] 1. Al between the joining surfaces of two aluminum materials
-Si based brazing filler metal, both aluminum materials
By applying a pressure of 1 to ²⁰ kgf / mm ^{2 in} the direction in which the joint surfaces are pressed together, and further applying ultrasonic vibration to at least one of the aluminum materials,
While destroying the oxide film on the joint surface of both aluminum materials and the oxide film on the surface of the brazing material, frictional heat is generated between the aluminum material and the brazing material, and the resulting frictional heat melts the brazing material A method for joining aluminum materials, which comprises brazing.