JPH06218536A - Joined parts formed by using phosphor-copper brazer - Google Patents

Abstract

PURPOSE:To provide the joined parts formed by using phosphor-copper brazer in such a manner that the parts are hardly corrosive even in the environment of an atmosphere where a sulfurizing gas exists. CONSTITUTION:A heat resistant coating material, such as, for example, aluminum paint 9, is applied at 3 to 30mum thickness to the exposed surfaces and heat-affected zones of fillet to be formed after joining. As a result, the fillet parts and joining members exposed with the ground surfaces of the joined parts do not come into direct contact with the sulfurizing gas even if these parts are used in the sulfurizing gaseous atmosphere. The corrosion of the joined parts by the sulfurizing gas is thus prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to parts joined by resistance heating using phosphor copper solder.

[0002]

2. Description of the Related Art A brazing method is widely used when joining members such as copper alloys in electric equipment.
For example, it is used for joining a contact, which is a current-carrying member, to a terminal, joining a terminal to a mesh copper wire, and the like. When joining these members by brazing, generally two methods are known. One is using Ag brazing filler metal and flux,
The other is a method of directly heating and joining with a gas flame, and another is resistance brazing, in which phosphor copper brazing is used, it is placed between the electrodes together with the joining member, and a large current is passed under pressure for heating. is there.

As described above, the joining method in which two members are heated by applying a large current while pressurizing the two members has higher productivity than the joining method in which heating is performed by a gas flame or the like. Further, as the brazing material, phosphorus copper brazing is cheaper than Ag brazing, and since brazing can be done without flux, the brazing time is shortened and the flux is removed after brazing. There are advantages that the steps can be omitted and the manufacturing cost can be reduced.

FIG. 6 is a schematic side view for explaining the arrangement of each member in the case of joining a Sn-plated terminal having a thickness of 1 to 2 μm and a mesh copper wire by resistance brazing. It is shown as. In FIG. 6, resistance brazing is performed by interposing a phosphor copper braze 3 between the mesh copper wire 1 and the terminal 2 and applying a large current while pressing the electrodes 4 and 5 from above and below.

FIG. 7 is a photomicrograph of the side surface appearance of the joint thus obtained at a magnification of 150 times, and FIG.
It is a schematic cross section for explaining the structure. In each of FIGS. 7 and 8, the common portions are represented by the same reference numerals so as to correspond to FIG. After joining, as shown in FIG. 8, the phosphor copper braze 3 is melted and extruded by heating, and this is cooled and solidified to form a fillet 6, and the mesh copper wire 1 and the terminal 2 are also formed.
It can be seen that the Sn plating 7 of No. 1 is melted and disappeared, and the exposed portion of the copper alloy background 8 is generated.

[0006]

However, the joining parts using the phosphor copper braze, which is low in manufacturing cost, has the following problems. This is because when electrical equipment having joint parts using phosphor copper braze is used in an environment where sulfide gas exists, such as in hot springs and sewage treatment plants, phosphorus with high vapor pressure in the brazing filler metal This is to vaporize and form vacancies therein, CuS is generated by the vacancies, the joint is sulfide-corroded, the joint strength is lowered, and finally the peeling occurs.

In addition, in a member plated with Sn, the exposed portion of the background of the copper alloy may cause sulfidation corrosion due to heating of brazing. In particular, twisted thin wires such as braided copper wire may even be broken due to this corrosion. As a countermeasure against this, plating may be performed after brazing, but the plating solution or water during washing may remain inside the mesh copper wire, which may cause corrosion during long-term use. The present invention has been made in view of the above points, and an object thereof is to provide a joining component using phosphorous copper braze that can maintain a long life even in an environment of an atmosphere in which a sulfide gas exists. Especially.

[0008]

In order to solve the above-mentioned problems, a joining part of the present invention using phosphor copper brazing has a heat-resistant paint such as aluminum paint on at least a fillet portion formed after joining. Is applied to a thickness of 3 to 30 μm, and the coating material is also applied to a joining member whose plating layer is lost during the joining process and the background is exposed.

[0009]

In order to achieve the above, the joint component of the present invention is
By applying aluminum paint to the exposed surface of the fillet and the heat-affected zone, even if this joint part is used in a sulfide gas atmosphere, the fillet portion and the exposed surface of the member do not come into direct contact with the sulfide gas and It is possible to prevent corrosion by gas.

[0010]

EXAMPLES The present invention will be described below based on examples. In this case as well, the case where the Sn-plated terminal and the mesh copper wire are resistance brazed using phosphor copper brazing as in the above will be described. After heat brazing, make sure that the atmosphere in use does not come into direct contact with the exposed copper alloy.
Fillet part, joint member affected by heat and its vicinity,
It was covered with heat resistant paint.

The side surface appearance of the obtained joint is shown in FIG. 1 as a photomicrograph at a magnification of 150 times, and a schematic sectional view of the joint is shown in FIG. 2 for explaining the structure. The reference numerals in FIGS. 1 and 2 are the same as those in FIGS. 6 to 8. In the present invention, as shown in FIG. 2, a fillet 6 formed after resistance heating brazing, and a portion of the copper net wire 1 where the Sn plating 7 has disappeared by heating and the copper alloy ground surface 8 of the terminal 2 are exposed to the aluminum coating material. Paint 9 was applied to a thickness of about 15 μm.

At this time, especially when the fillet 6 is corroded, it causes peeling from the joint portion.
At least fillet 6 needs to be coated with aluminum paint 9 and, in consideration of the life of the electric equipment to which this joint part is attached, the exposed portion of the copper alloy background is also coated with aluminum paint 9 depending on the actual condition. It is better to apply it.

Aluminum paint 9 used here
When used as a current-carrying component, it is necessary to select a paint with good heat resistance from the viewpoint of heat generation due to current flow.
For example, aluminum paint specified in Japanese Industrial Standard (JIS) K5492 is suitable, but not limited to aluminum paint, as long as it has adhesiveness or heat resistance equal to or higher than this, similar effects can be obtained. Obtainable. With respect to the thickness to be applied, when the thickness is 3 μm or less, there may be a part that is not partially applied due to bubbles or the like contained in the paint at the time of application, and when the thickness exceeds 30 μm. The coating thickness of the aluminum paint 9 is 3 because the paint easily peels off when this joint part is mechanically operated.
It is suitable to be set to ˜30 μm.

Next, a sulfidation corrosion test was carried out using the above-mentioned joined component sample obtained by the present invention. Test condition is H
₂ S gas concentration 3ppm, temperature 40 ° C, relative humidity 85%,
The test period is 10 days. After the lapse of 10 days, the sample was taken out, and the decrease rate of the shear strength of the joint before and after the sulfidation corrosion test and the presence or absence of corrosion due to aluminum paint were examined. The shear strength reduction rate is calculated by the following equation.

[0015]

[Equation 1] However, W ₀ : Shear strength before sulfidation corrosion test (Kgf / mm ² ) W ₁ : Shear strength after sulfidation corrosion test (Kgf / mm ² ) Table 1 shows the obtained test results. For comparison, Table 1 also shows the results of the same sulfidation corrosion test as described above for the conventional joint parts using the same member and not coated with aluminum paint.

[0016]

[Table 1] From the results in Table 1, it can be seen that the present invention significantly improves the shear strength reduction rate. Regarding the corrosion state after the sulfidation corrosion test, the appearance of the jointed part of the present invention is shown in FIG. 3 and the appearance of the conventional jointed part is shown in FIG. From these micrographs, the joint part of the present invention in FIG. 3 shows no signs of corrosion in the area coated with the aluminum paint 9, but the conventional joint part not coated with the aluminum paint 9 in FIG. It is observed that the sulfide 10 which is corroded in black is generated. FIG. 5 is a micrograph showing that the thickness of the sulfide 10 is 3 to 6 μm, and the effectiveness of the present invention is clear from FIGS. 3 to 5.

The joining parts using the phosphor copper braze of the present invention have been described above by taking the case of joining the net copper wire and the terminal as an example, but it is effective to apply aluminum paint after joining as described above. Is not limited to the joining of copper wire and terminals, and it can be applied to many other machines and devices other than electrical equipment, and can be applied to many parts that are joined using phosphor copper solder. Is something that can be done.

[0018]

EFFECTS OF THE INVENTION The joining part using the phosphor copper brazing material of the present invention is applied to the joint after brazing with aluminum paint.
Since the joint does not come into direct contact with the atmosphere and is not corroded, no peeling occurs from the fillet formed by melting and solidifying the phosphor copper braze. Also, regarding the bare surface that is exposed by the plating of the joining members being melted during the joining process,
It can prevent corrosion and maintain a long life.

[Brief description of drawings]

FIG. 1 is a photomicrograph showing a side view of a joined component of the present invention.

FIG. 2 is a schematic cross-sectional view of a joint for explaining the structure of the joint component of the present invention.

FIG. 3 is a photomicrograph showing the appearance of the joint after the sulfidation corrosion test of the joint part of the present invention.

FIG. 4 is a photomicrograph showing the appearance of a joint after a sulfidation corrosion test of a conventional joint part.

5 is a micrograph showing the thickness of the sulfide in FIG.

FIG. 6 is a schematic diagram showing the arrangement of each member when resistance brazing a terminal and a mesh copper wire.

FIG. 7 is a micrograph showing the appearance of the joint between the terminal and the braided copper wire after resistance brazing.

8 is a schematic cross-sectional view for explaining the structure of the joint portion in FIG.

[Explanation of symbols] 1 copper wire 2 terminal 3 phosphorous copper brazing 4 electrode 5 electrode 6 fillet 7 Sn plating 8 copper alloy background 9 aluminum paint 10 sulfide

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[Procedure amendment]

[Submission date] February 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a photograph showing a metallographic structure on a side surface of a joined component of the present invention.

FIG. 2 is a schematic cross-sectional view of a joint for explaining the structure of the joint component of the present invention.

FIG. 3 is a photograph showing the metallographic structure of the joint after the sulfidation corrosion test of the joint of the present invention.

FIG. 4 is a photograph showing a metallographic structure of a joint after a sulfidation corrosion test of a conventional joint part.

FIG. 5 is an enlarged photograph of a metal structure showing the sulfide portion of FIG.

FIG. 6 is a schematic diagram showing the arrangement of each member when resistance brazing a terminal and a mesh copper wire.

FIG. 7 is a photograph showing the metallographic structure of the joint between the terminal and the braided copper wire after resistance brazing.

8 is a schematic cross-sectional view for explaining the structure of the joint portion in FIG.

[Explanation of symbols] 1 copper wire 2 terminal 3 phosphorous copper brazing 4 electrode 5 electrode 6 fillet 7 Sn plating 8 copper alloy background 9 aluminum paint 10 sulfide

Claims (4)

[Claims] 1. A joint part in which two members having a plating layer on the surface are joined using phosphor copper solder, wherein a heat resistant paint is applied to at least an exposed surface of a fillet formed after the joining. Joined parts made of sapphire copper solder. 2. The joining part according to claim 1, wherein the region to which the heat resistant coating is applied includes a range where the plating layer of the joining member is lost in the joining process. parts. 3. The joint component according to claim 1 or 2, wherein the heat-resistant paint is applied to a thickness of 3 to 30 μm using phosphor copper solder. 4. The joint component according to any one of claims 1 to 3, wherein the heat resistant paint is aluminum paint.