JPH07284984A - Brazing method of high-strength high conductivity copper alloy material and iron and steel mateerial - Google Patents

Abstract

PURPOSE:To provide a brazing method of a high-strength high-conductivity copper allay material and mild steel material suitable for use at a high temp. by enhancing the strength of joint parts without causing softening of both metals at the time of joining. CONSTITUTION:The high-strength high-conductivity copper alloy material and the mild steel material are joined at a temp. not exceeding 450 deg.C by using a brazing filler metal consisting of Au-3.15%Si(gold-3.15% silicon), by which a joint boundary layer of the melting temp. higher than the melting temp. of the brazing filler metal is formed between both materials. A Cu-Cr-Zr alloy is adopted as the high-strength high-conductivity copper alloy material. The joining operation using the brazing filler metal is executed at >=363 deg.C which is the melting temp. of the Au-3.15%Si brazing filler metal and <=450 deg.C which is a temp. range where the Cu-Cr-Zr alloy is not softened. The flux for stainless steels is adopted at the time of the joining operation and the actual brazing temp. is set at 420 to 430 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing method of a steel material and a high strength and high conductivity copper alloy material used for an end ring of a rotary machine, a bellows of a vacuum circuit breaker, or a lead frame of electronic parts. is there.

[0002]

2. Description of the Related Art Conventionally, as a method for joining a copper alloy and a steel material, soldering, silver brazing, or welding means has been widely used. Soldering is a method that is easily adopted when the target member is small, and silver brazing is used when the target member has large dimensions and the joint requires high mechanical strength. It Further, the welding means does not require mechanical strength, and is used in a case where both materials are simply joined.

On the other hand, a high-strength and high-conductivity copper alloy material has been developed which maintains the strength at high temperature without deteriorating the conductivity of copper. For example, silver-containing copper to which about 0.2% of silver is added. A Cu-Cr alloy obtained by adding about 1% of chromium to copper, and a Cu-Cr-Zr alloy material obtained by adding about 0.3% of zirconium to the alloy are known.

Generally, copper has a property of softening at a temperature of more than 200 ° C., but the Cu-Cr-Zr alloy has a characteristic that it does not soften even when heated to about 450 ° C.

[0005]

However, Cu-Cr-Zr as such a high-strength and high-conductivity copper alloy material is used.
When joining an alloy and a steel material, softening of both metals does not occur during soldering, but both the strength and melting temperature of the joint are low, and it is not suitable for use at high temperatures such as end rings of rotating machines. There's a problem.

The Cu-Cr-Zr alloy is 700
When Cu-Cr-Zr alloy itself is softened when it is brazed by heating it to a high temperature of ℃ to 800 ℃, the desired hardness cannot be maintained and the heat resistance during use is lost. There is a difficulty to be seen. Usually, the Cu-Cr-Zr alloy has a Vickers hardness of 162 before silver brazing, but the Vickers hardness of 76 after silver brazing at 750 ° C is 76, and the hardness of the alloy by the heating operation of brazing is Softens to about 1/2.

Further, when the Cu-Cr-Zr alloy and the steel material are joined by welding means, the Cu-Cr-Zr alloy is used.
The alloy may crack, and therefore welding means are not suitable for joining both metals.

[0008] As described above, when joining the high-strength and high-conductivity copper alloy material and the steel material, the conventional soldering, silver brazing or welding means do not provide satisfactory results. At present, a method of joining at a temperature of about 450 ° C. without lowering the mechanical strength has not been realized.

Therefore, the present invention solves the problem of the conventional method of joining a high-strength and high-conductivity copper alloy material and a steel material, so that softening of both metals does not occur during joining and It is an object of the present invention to provide a brazing method for increasing the strength of a part and suitable for use at high temperature.

[0010]

In order to achieve the above-mentioned object, the present invention uses a high-strength and high-conductivity copper alloy material and a steel material as Au-3.15% Si (gold-3.15% silicon). A high-strength and high-conductivity copper, which is formed by joining the base metal brazing material at a temperature not exceeding 450 ° C. to form a bonding boundary layer having a melting temperature higher than the melting temperature of the brazing material between the two materials. Provided is a brazing method of an alloy material and a steel material.

As a high strength and high conductivity copper alloy material, Cu-
The joining operation using the Cr-Zr alloy and the brazing material is 363 which is the melting temperature of Au-3.15% Si brazing material.
It is carried out at a temperature of 450 ° C. or higher, which is a temperature range in which the Cu—Cr—Zr alloy does not soften. In addition, a flux for stainless steel is adopted during the joining work, and the actual brazing temperature is 420 ° C to 430 ° C.

[0012]

[Operation] According to the method of joining the high-strength and high-conductivity copper alloy material and the steel material, the hardness of both materials before and after the brazing is not changed, and the hardness of the boundary layer after the joining is the steel material. A value close to the Vickers hardness of 1 is obtained, and there is no fear that the joint boundary layer will be melted by reheating.

This is because an alloy layer of gold and copper was formed in the joining boundary layer of both metals, and the Vickers hardness was increased and the melting temperature was increased, so that softening of both metals did not occur during joining. The strength of the joint is increased, and the unique effect of being suitable for use at high temperature is obtained.

[0014]

EXAMPLES Examples of the method for brazing a high-strength and high-conductivity copper alloy material and a steel material according to the present invention will be described below. In this embodiment, Cu-Cr as a high strength and high conductivity copper alloy material is used.
When a brazing material that can be joined at a temperature not exceeding 450 ° C. when joining a Zr alloy and a steel material was investigated, it was found that Au-3.15% Si (gold-3.15% silicon). ) Found that the brazing material of () is suitable.

The melting temperature of this Au-3.15% Si brazing material is 363 ° C., and gold (Au) in the brazing material is copper (Cu).
And reacts with both metals of iron (Fe) to form an alloy.

The brazing work must be carried out at 363 ° C. or higher at which the Au-3.15% Si brazing material melts and at 450 ° C. or lower, which is a temperature range in which the Cu—Cr—Zr alloy does not soften.

In the practice, a commercially available flux for stainless steel was used as the brazing flux, and the brazing temperature was 420 ° C. to 430 ° C., so that a good joint was obtained.

Table 1 shows the results of measuring the Vickers hardness of the Cu-Cr-Zr alloy and the steel material before and after brazing.

[0019]

[Table 1]

According to Table 1, Cu-Cr before and after brazing
-The Vickers hardness of the Zr alloy material and the steel material did not change, and the hardness of the boundary layer after joining was Vickers hardness of 310, which is the Vickers hardness of the steel material 31.
It is close to 3.

Further, the melting temperature of the bonding boundary layer is Au-
It was found that the melting temperature of the 3.15% Si brazing material was higher than 363 ° C, and there was no fear of melting due to reheating. This is because, as seen in the Au-Cu metal phase diagram of FIG. 1, an alloy layer of gold and copper is formed on the bonding boundary layer to increase the Vickers hardness and increase the melting temperature. Be considered.

[0022]

As described in detail above, according to the method for joining a high-strength and high-conductivity copper alloy material and a steel material according to the present invention, the hardness of both materials before and after brazing changes. Since the hardness of the boundary layer after joining is almost the same as the Vickers hardness of steel materials, the strength of the joint is increased, and it is mainly used for end rings of rotary machines and bellows of vacuum circuit breakers. It is effective when applied to parts used at high temperatures.

In particular, since an alloy layer of gold and copper is formed at the above-mentioned joint, the melting temperature is raised and there is no fear that the boundary layer is melted by reheating, and softening of both metals occurs at the time of joining. There is no fear. Furthermore, the "cracking" phenomenon that tends to occur when the above copper alloy material and steel material are joined by welding means is prevented, the mechanical strength of both materials is increased, and a brazing method suitable for use at high temperature is provided. Can be provided.

[Brief description of drawings]

FIG. 1 is a metal phase diagram of Au—Cu.

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Claims (4)

[Claims] 1. A high-strength and high-conductivity copper alloy material and a steel material are joined at a temperature not exceeding 450 ° C. by using a brazing material of Au-3.15% Si (gold-3.15% silicon). A brazing method of a high-strength and high-conductivity copper alloy material and a steel material, characterized in that a joining boundary layer having a melting temperature higher than the melting temperature of the brazing material is formed between both materials. 2. The high-strength and high-conductivity copper alloy material,
The brazing method for a high-strength and high-conductivity copper alloy material according to claim 1, which uses a Cu-Cr-Zr alloy, and a steel material. 3. The joining operation using the brazing material is Au-
At 363 ° C or higher, which is the melting temperature of 3.15% Si brazing material,
The brazing method of the high-strength and high-conductivity copper alloy material and the steel material according to claim 1 or 2, which is carried out at 450 ° C or lower, which is a temperature range in which the Cu-Cr-Zr alloy does not soften. 4. A flux for stainless steel is adopted at the time of joining work using the brazing material, and the brazing temperature is 420 ° C. to 4 ° C.
The brazing method of the high-strength and high-conductivity copper alloy material and steel material of Claim 1, 2 and 3 which were 30 degreeC.