JPS5832573A - Brazing method by inverting current arc - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum brazing method, and particularly to a joining method suitable for removing an oxide film on a joining surface.

Brazing of aluminum or aluminum alloys has conventionally been carried out using an HT-Si brazing filler metal containing 5 to 12 percent by weight of Sl, and using a norogenide salt as a flux. However, this conventional brazing method has the drawback that the flux is highly corrosive, and that it takes time to remove the flux after brazing. Additionally, flux vapor is generated during brazing, which poses problems in terms of workability and pollution.

The purpose of the present invention is to destroy the oxide film on the surface of the materials to be joined by the cleaning action generated when the current waveform is positive on the electrode due to the reversal current arc, and to create a solder suitable for aluminum.
Provides a method of attachment.

The present invention is a method of joining dissimilar materials made of aluminum, aluminum alloys, or one of these alloys and another member by utilizing the multi-leaning action of a reversing current arc.

The main points of the present invention will be described below.

FIG. 1 shows the principle of the cleaning action by the reversing current arc of the present invention. When the reverse current supplied from the power source 5 is positive at the electrode, the cations in the arc 4 from the electrode 1 are accelerated by the cathode fall and collide with the cathode on the surface of the workpiece 20 at high speed, so that the oxide film 3 is Destroy. Since the area through which this cathode spot passes is covered with an inert gas atmosphere of Ar gas, the oxide film 3 is not formed again. FIG. 2 shows the current waveform of the reverse current arc supplied from the power source 5. When the upper electrode is positive, the oxide film 3 on the surface of the material to be joined 2 is removed by a cleaning action, and a clean surface is formed. Note that when the lower electrode is negative, the material to be joined 2 is heated to stabilize the arc 40 and prevent the electrode 1 from being worn out. FIG. 3 shows an overview of the brazing method of the present invention.
In the figure, arrows indicate the order of the brazing process, and the end faces and surfaces of the materials 2 to be brazed are covered with an oxide film 3. 5 After that, the above-mentioned oxide film 3 is destroyed by the reversal current arc 4 generated from the electrode 1, and the brazing filler metal 6 supplied into the gap between the welded materials 2 and 2' is caused by the arc 4 Since it is heated by

Examples of the present invention will be described below. As brazing performance evaluation methods, the method of the present invention and the conventional σ) torch brazing method were employed, and wettability tests as shown in Table 1 were conducted.

] Bonding material 2 is A1050 (0.02% Cu, 0.10% S
;, o, 1% PE, 0.02% Mn+remaining At) aluminum plate was used. First, after cleaning the surface of the bonding material 2, flux was added in the conventional method, and a reverse current arc was generated in the method of the present invention. Then, at the place where the flux or clean surface was obtained, S with a diameter of 5 φ and a thickness of 3 m +:
In the conventional method, a brazing filler metal made of aluminum alloy containing 0 and X% was placed and heated in a furnace.

In the method of the present invention, the arc is generated again and the bonding material 2 is
It was heated until it reached 80-610C. Figure 4 shows the test results. In the figure, the horizontal axis represents the time ratio between negative electrode and positive electrode current waveforms according to the method of the present invention, and the horizontal axis represents the wettability ratio. The larger the wettability ratio, the easier the brazing filler metal is to fit in with the brazing material, which means that the bondability is better. The wettability ratio is &3 in the conventional method, but in the case of the present invention, it varies depending on the time ratio of the negative electrode and the positive electrode, and the wettability ratio increases as the time ratio increases. It has been found that in order to obtain a wettability ratio equal to or higher than that of the conventional method, the time ratio between electrode minus and electrode plus should be set to 5 or more.

In addition, using the same method as the above wettability test, the brazing filler metal was
The n-At system is used, and the furnace heating or arc heating temperature is set to 45
Although the temperature was set to 0C, almost the same data as shown in FIG. 4 was obtained.

Next, the time ratio of electrode minus and electrode plus shown in Figure 5 is 6.
Using a reversing current arc, a joint specimen shown in FIG. 3 was prepared and brazed. The material to be joined 2 has a diameter of 2Ifilφ
A10'50BE (0.02% Cu.

It is an extruded aluminum rod with 0.10%3i, 0.1%pe, o, o2%Mn, and the rest Al), and the material to be joined is 2゜2'.
They faced each other with a gap of 0.2 W+. Next 1.0■
Use a tungsten electrode 1 with a diameter of φ, and connect the electrode 1 and the material to be welded 2.
0 gap to 1. A reversal current arc 4 was generated in an atmosphere with a gas flow rate of 3 t/#. After that, Ar
A sialuminium alloy containing 10% of 5i was inserted as a brazing material 6 between the materials to be joined 2 and 2' in a gas atmosphere. the result,
The vicinity of the abutting portions of the materials to be joined 2 and 2' had a metallic luster due to the cleaning action, and the oxide film 3 was destroyed. or,
The wettability of the brazing filler metal 6 was good, and evidence of bonding was observed. After brazing, a tensile test was conducted on the joint, but the tensile strength was 8.
．． It was 2 breast f/2, yield strength 3.4 and 9 f/2, and the performance was the same as or better than that of the base material.

According to the present invention, the oxide film on the surface of the materials to be joined can be removed by the cleaning action of the reverse current arc, resulting in the following effects. 1) No flux is required, and there is no need to remove flux after bonding. 2) By optimizing the time ratio between the negative electrode and the positive electrode of the reversal current arc, the torsion ratio can be increased to 1.4 times or more compared to the conventional one. 3) By selecting an appropriate brazing material, the heating temperature can be lowered.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a model diagram of the current waveform used in the present invention, Fig. 3 is a schematic diagram showing the process of the present invention, Fig. 4 is an explanatory diagram of experimental results, and Fig. 5 shows a model diagram of the current waveform. 1... Electrode, 2... Joined material, 3... Oxide film,
4... Reversing current arc, 5... Power source, 6... Brazing metal. $1 Evil grass 2 eyes 3rd gall ↓ ``===2=ko

Claims (1)

[Claims] 1. In a method of brazing materials to be joined in an inert gas atmosphere, the surface of the materials to be joined is cleaned by the cleaning action generated when the current waveform of the electrode is positive due to a reversal current TIG arc. A brazing method using a reversal current arc, which is characterized in that a brazing metal is then supplied. 2. A brazing method using a reversal current arc as set forth in claim 1, characterized in that the time ratio of the electrode positive and negative electrodes of the current waveform due to the reversal current TIG arc is set to 5 or more. 3. A brazing method using a reversing current arc as set forth in claim 1 or 2, wherein the material to be welded is aluminum or an aluminum alloy.