KR20060082515A - Method for manufacturing contact materials for vacuum interpreter and contact materials manufactured thereby - Google Patents

Abstract

The present invention manufactures a Cu-Cr-based contact material using vacuum casting instead of the conventional sintering method, infiltration method, and arc melting method, and ages it so that spherical Cr precipitates are uniformly precipitated in the Cu base, thereby providing very high mechanical and electrical properties. The present invention relates to a method of manufacturing a contact material for a vacuum circuit breaker, and a contact material manufactured thereby.

In order to achieve the above object, a method of manufacturing a contact material for a vacuum circuit breaker according to the present invention is to ingot by solidifying a raw material of 20% to 95% Cu and 5% to 80% Cr by weight in a non-oxidizing atmosphere and then solidifying it. (ingot) for the casting step, the ingot prepared ingot for 30 minutes to 2 hours at 800 ~ 1070 ℃ temperature and the solution ingot (ingot) for 30 minutes at 400 to 700 ℃ temperature Aging for time.

Vacuum circuit breaker, vacuum casting method, solution treatment, aging treatment

Description

Method for manufacturing contact material for vacuum breaker and contact material manufactured by the same {Method for manufacturing contact materials for vacuum interpreter and contact materials manufactured}

1 is a view showing the configuration of a general vacuum circuit breaker.

Figure 2 is a structure photograph of a contact material for a conventional vacuum circuit breaker.

Figure 3 is a graph showing the change in tensile strength according to the Cr content of the contact material for a vacuum circuit breaker according to the present invention.

Figure 4 is a graph showing the change in electrical conductivity according to the Cr content of the contact material for the vacuum circuit breaker according to the present invention.

Figure 5 is a structure photograph of the contact material for the vacuum circuit breaker according to the present invention.

6 is a diagram showing a part of a state diagram of Cu-Cr.

Figure 7 is a tissue photograph before the processing according to the present invention.

8 is a tissue photograph after the processing according to the present invention.

Figure 9 is a graph showing the change in hardness according to the aging treatment temperature of the contact material for the vacuum circuit breaker according to the present invention.

10 is a graph showing the change in electrical conductivity according to the aging treatment temperature of the contact material for a vacuum circuit breaker according to the present invention.

※ Explanation of symbols about main part of drawing ※

1: cylindrical ceramic insulation case 2,3: stainless terminal board

4: upper pedestal 5: lower pedestal

6: cylindrical shield 7: fixed electrode

8: moving electrode 9: bellows

The present invention relates to a method for manufacturing a contact material for a vacuum circuit breaker and a contact material produced by the same, and more specifically, to a vacuum casting and The present invention relates to a method of manufacturing a contact material for a vacuum circuit breaker which improves mechanical and electrical properties required as a contact material by manufacturing through aging treatment, and a contact material manufactured thereby.

Vacuum circuit breakers are widely used in various industrial power equipments and distribution equipments because of their excellent breaking and insulating performance, simple structure, small size and light weight, easy maintenance and maintenance, and environmental friendliness. 1 shows the configuration of such a vacuum circuit breaker. A container composed of a cylindrical ceramic insulating case 1 and stainless terminal boards 2 and 3 is provided, and the inside of the container is maintained in a high vacuum state of 10 ⁻⁵ to 10 ⁻⁸ Torr. A pair of electrodes 7 and 8 made of a contact material is provided inside the container. Of the pair of electrodes 7 and 8, the fixed electrode 7 is fixedly installed on the upper pedestal 4, and the movable electrode 8 provided to be spaced apart from the fixed electrode 7 by a predetermined distance is attached to the bellows 9. It is installed on the lower pedestal 5 installed so as to be movable. The cylindrical shield 6 installed to surround the pair of electrodes 7 and 8 is formed by attaching to the inner surface of the insulating case 1 by evaporating or scattering the components of the contact material due to the arc heat generated when the current is interrupted. To prevent it.

Since the contact material used as an electrode in the vacuum circuit breaker configured as described above is used in harsh conditions such as high voltage, high current and high heat (arc heat), the following characteristics are required.

1) High mechanical strength and less plastic deformation (the higher the mechanical strength, the better the blocking performance).

2) High hardness and good wear resistance and welding resistance (reduce contact wear when arc is generated to prevent components from evaporating or scattering).

3) High electrical conductivity (low contact resistance and high conductance).

4) High thermal conductivity (excellent blocking performance and rapid discharge of arc heat).

[Contact Materials for Vacuum Switching Devices, published in U.S. Patent No. 5,882,488 (1999), U.S. Patent No. 4,870,231 (1989), 1993, IEEE Plasma Science Report, Vol. IEEE Transactions on Plasma Science, Vol. 21, No. 5, (1993) pp. 447)]

Cu-Bi, Cu-Pb, Cu-Co-Bi, Cu-Co-Pb, Cu-Cr, Cu-Cr-Bi, Cu-Cr-Pb and the Although the same alloys have been used, most of the large current circuit breakers since the 1990s because the low melting point metals such as Bi and Bb were easily deteriorated, scattered, and evaporated when they repeatedly blocked large currents. Cu-Cr alloy is used as the contact material of the.

As a manufacturing method of such a Cu-Cr-based contact material, the sintering method, the infiltration method, the arc melting method, and the like have been mainly used, and these methods will be briefly described.

In the sintering method, the Cu powder and the Cr powder are uniformly mixed, and then the mixed powder is put into a mold and pressurized to form a molded body, which is then sintered in a solid or liquid state under a hydrogen or vacuum atmosphere to prepare a contact material.

The infiltration method forms a molded body by pressing Cr powder or Cu-Cr mixed powder, and then preliminarily pre-sintered in hydrogen or a vacuum atmosphere to produce a pre-sintered body having a constant strength. A Cu plate (or a piece) is placed on the presintered body and then heated above the melting temperature of Cu to allow molten Cu to be sucked into the internal voids of the presintered body by capillary action to produce a contact material.

In the arc melting method, Cu powder and Cr powder are mixed, molded into a desired shape / size, and plasticized to prepare an electrode. The electrode is mounted in an arc melting furnace to contact the crucible to generate an arc, and the arc heat causes the electrode to dissolve and drops to the bottom of the water-cooled crucible in the form of droplets, which are then quenched simultaneously with degassing to produce ingots. This ingot is cut to a suitable size and used as a contact material.

A representative method for manufacturing a contact material by the sintering method or the infiltration method is disclosed in Korean Patent Publication No. 2002-44751. This manufacturing method comprises a mixing step of mixing each powder of copper (Cu), chromium (Cr), heat-resistant element (X) to obtain a mixed powder; A molding step of molding the mixed powder to obtain a molded body; Sintering step of sintering the molded body at a temperature of 900 ~ 1075 ℃ to obtain a sintered body (this sintering step is a step of pre-sintering the molded body below the melting point temperature of copper to form a porous pre-sintered body and placing a copper plate on the pre-sintered body Heating to a temperature above the melting point of copper so that the copper liquid may be infiltrated into the porous presintered body); The sintered body consists of a post heat treatment step of applying heat at 1100 to 1850 ° C. for 0.5 to 20 hours.

However, this manufacturing method has a problem in that fine pores exist inside the contact material due to the limitation of powder metallurgy. These internal voids lower the mechanical strength and hardness of the contact material, hinder the movement of electrons, and lower the electrical conductivity. In addition, foreign matter (cutting oil, gas, moisture, etc.) remains in the void during subsequent processing, contaminating the interior of the vacuum circuit breaker. In order to remove such foreign matter, a high temperature post-heat treatment process may be performed for a long time, which complicates the production process and increases the manufacturing cost. However, even after the post-heat treatment described above, the maximum filling rate is only 98.5%, so that micropores still exist.

Looking at the structure of the contact material produced by the sintering method, as shown in Fig. 2, amorphous Cr precipitates are unevenly distributed in the Cu matrix. This impedes the movement of electrons and lowers the electrical and thermal properties of the contact material such as electrical conductivity and thermal conductivity. Moreover, when the Cr content exceeds 50%, the Cu powder and the Cr powder are not uniformly mixed, which increases the nonuniformity of the sintered body, which further lowers the electrical and thermal properties of the contact material.

A representative method for manufacturing a contact material by the arc melting method is disclosed in Korean Patent Laid-Open Publication No. 1999-019081. According to the manufacturing method described as Example 1 in the above patent specification, 70 wt% of Cu powder, 20 wt% of Cr powder, and 10 wt% of V powder are mixed and then V is formed in a vacuum atmosphere to form a solid solution in the Cu matrix. Melt to a temperature that can be produced to prepare a contact material. The structure of the material shows that 3-4% V solid solution and a small amount of chromium solid solution are formed in the Cu base, which results in excellent withstand voltage and high current interruption characteristics.

However, according to this arc melting method, the molten alloy is not sufficiently stirred, causing local non-uniformity of the composition and solidification structure of the alloy, and in some cases, cracking occurs. This not only lowers the electrical conductivity and thermal conductivity of the contact material, but also decreases the mechanical strength, thereby shortening the life of the product.

The present invention has been proposed to solve this problem, and spherical Cr precipitates are uniformly precipitated in the Cu base by preparing Cu-Cr-based contact materials by vacuum casting and aging instead of the conventional sintering, infiltration, and arc melting methods. The purpose is to provide a method for producing a contact material excellent in mechanical and electrical properties.

Another object of the present invention is to provide a method for manufacturing a contact material for a vacuum circuit breaker having better mechanical and electrical properties by performing a process such as extrusion, drawing, forging before aging after vacuum casting the contact material.

In order to achieve the above object, a method of manufacturing a contact material for a vacuum circuit breaker according to the present invention is to ingot by solidifying a raw material of 20% to 95% Cu and 5% to 80% Cr by weight in a non-oxidizing atmosphere and solidifying it. (ingot) for the casting step, the ingot prepared ingot for 30 minutes to 2 hours at 800 ~ 1070 ℃ temperature and the solution ingot (ingot) for 30 minutes at 400 to 700 ℃ temperature Aging for time.

In addition, the casting step may include the step of processing the manufactured ingot at a processing ratio of 50 to 90% at a processing temperature of 800 to 1000 ℃ by one of the processing method of extrusion, drawing, forging.

Hereinafter, a method of manufacturing a contact material for a vacuum circuit breaker according to the present invention will be described in detail with reference to the accompanying drawings. The biggest feature of the present invention is to use the vacuum casting method instead of the conventional sintering method, infiltration method, arc melting method to manufacture the contact material, and to undergo a solution treatment and an aging treatment process as a post-heat treatment process.

First, according to the vacuum casting method, a raw material of 20 to 95% Cu and 5 to 80% Cr by weight is completely melted in a vacuum atmosphere and then solidified, thereby preparing an ingot. Currently, the Cu-Cr-based alloy, which is most commonly used as a material for contact materials, varies greatly in mechanical and electrical properties of contact materials depending on the content of Cr. FIGS. 3 and 4 show the Cr content of the ingot manufactured by vacuum casting. The change in tensile strength and electrical conductivity is shown.

As shown in Fig. 3, the tensile strength of the ingot is increased as the content of Cr increases. More specifically, the Cr content increases sharply in the section of 5 to 40%, gradually increases in the section of 40 to 80%, and becomes almost saturated at 80% or more. This increase in tensile strength not only extends the life of the contact material but also improves the high current breaking performance. Therefore, in view of mechanical strength, the content of Cr is preferably contained 5 to 80%.

Referring to FIG. 4, which shows the change in electrical conductivity according to Cr content, it can be seen that the electrical conductivity rapidly decreases until the Cr content reaches 5%, and remains almost constant thereafter. In the metal structure, Cr is present in the form of a solid solution or a precipitate, which acts as an obstacle to the movement of electrons, so the electrical conductivity decreases with increasing Cr content. However, the electrical conductivity can be improved through the aging treatment, which is a post-heat treatment process, so it does not need to be greatly considered in determining the content of Cr.

According to the present invention, one or two or more alloying elements of Bi, Te, and Pb may be included in the Cu—Cr alloy material having the above content ratio. Bi. Both Te and Pb improve welding resistance and prevent the contact material from being welded during arc generation. If the content of the weldable alloy element is less than 0.1%, the effect of preventing welding is insignificant, and if it exceeds 3.0%, fume is generated during vacuum casting, which not only lowers workability but also precipitates in a subsequent heat treatment process, thereby causing mechanical properties. Lowers.

On the other hand, Cr is a very sensitive oxidizing metal, and when melted in the air, it is combined with oxygen to form an oxide. It exists as a metal inclusion in the tissue of the ingot, which not only reduces the mechanical strength of the contact material, but also adversely affects the wear resistance and the welding resistance. Therefore, melting of the Cu—Cr based alloy should be performed in a non-oxidizing atmosphere. In actual operation, many non-oxidizing atmospheres use vacuum, Ar, and N ₂ atmospheres. In order to examine the effect of each atmosphere on the product quality, Cu-Cr alloy is melt-cast in each atmosphere and then The amount of gas contained in was measured, and the results are shown in the following [Table 1].

Table 1

Kinds Vacuum atmosphere Ar atmosphere N ₂ atmosphere Gas content (PPM) 150 or less 300-500 300-500

Compared to the average gas content of the contact materials produced by the conventional sintering method of 400 to 800 PPM, the above-mentioned vacuum, Ar, N ₂ atmosphere all improve the quality of the final product. In particular, since the gas content in the alloy can be controlled to 150 PPM or less in a vacuum atmosphere, an ingot of a very healthy structure can be produced.

FIG. 5 shows a photograph of the structure of the ingot manufactured by the vacuum casting method. Comparing this with FIG. 2 which is a structure photograph of a contact material manufactured by a conventional sintering method, it can be seen that the contact material according to the present invention has a structure characteristic as follows.

First, in the prior art, amorphous Cr precipitates with many corners are unevenly distributed, whereas spherical Cr precipitates with rounded corners are uniformly distributed in the ingot according to the present invention. The spheroidization of Cr precipitates improves the current blocking characteristics and dielectric breakdown voltage of the contact material by eliminating the concentrated source phenomenon of the electric field. In addition, the uniform distribution of the precipitates shortens the passage of electron transfer, thereby improving electrical conductivity and thermal conductivity.

Second, although the size of Cr precipitates in the prior art is 100 ~ 200㎛, according to the present invention is very fine as 20 ~ 30㎛. This increases the mechanical strength of the contact material.

Third, the conventional sintered body can easily find fine pores because the filling rate is about 98%, but in the present invention, the solidification is solidified after completely melting, and thus shows a filling rate of 100%. Therefore, the electrical conductivity and mechanical strength are excellent, and foreign matters (cutting oil, gas, moisture, etc.) are interposed in the pores to prevent the vacuum breaker from being contaminated.

The ingot manufactured by the vacuum casting method as described above may have more excellent mechanical and electrical properties through a post heat treatment process. The post-heat treatment process according to the present invention largely consists of a solution treatment and an aging treatment process.

The solution treatment is a process in which the ingot is heated to 800 to 1070 ° C. prior to the aging treatment and then maintained for 30 minutes to 2 hours to redissolve the Cr precipitates distributed in the Cu matrix by the solid solution limit in Cu. 6 shows a part of a state diagram of Cu-Cr. At room temperature, the Cr solid solubility in Cu base is almost 0, so most of Cr is present as precipitate. However, when the ingot is heated to 1070 ° C, Cr solid solution in the Cu matrix rises to 0.65% as shown in Fig. 6, so that the Cr precipitates are redissolved by this amount. As the amount of redissolved increases, the amount of Cr precipitated in the subsequent aging treatment process increases, thereby increasing the mechanical strength due to the precipitation strengthening effect. However, when the solution treatment temperature is higher than 1070 ° C, a part of the ingot is changed into a liquid phase, so that the heat treatment can no longer be performed. If the solution treatment temperature is lower than 800 ° C., the solubility of Cr falls below 0.2%, and even subsequent aging treatment does not bring sufficient strength increase effect. Therefore, it is preferable that solution treatment temperature is 800-1070 degreeC.

The solution treatment time is preferably 30 minutes to 2 hours. If the solution treatment time is less than 30 minutes, the Cr precipitates do not have sufficient time to completely dissolve until the solid solution limit. Therefore, if the solution treatment time exceeds 2 hours, the grains of Cu matrix are coarsened to increase the mechanical strength of the final product. Lowers.

On the other hand, the aging treatment is a step of reprecipitating Cr dissolved in the solution treatment process into Cu base by maintaining the solution-treated ingot at 400 to 700 ° C for 30 minutes to 2 hours. At this time, the precipitated Cr is not only much finer than the Cr precipitate that existed before the solution treatment, but also uniformly distributed in the Cu matrix. In this way, when the Cr dissolved in the Cu substrate is released as a precipitate, not only the mechanical properties of the ingot are improved due to the precipitation hardening effect, but also impurities are eliminated in the Cu, which facilitates the movement of electrons, thereby improving the electrical conductivity. If the aging treatment temperature is lower than 400 ℃, the precipitation hardening effect is inferior because it does not provide enough diffusion energy for precipitation of Cr, whereas if the aging treatment temperature is higher than 700 ℃, the difference from the solution treatment temperature (800 ~ 1000 ℃) does not have a large difference 6 As can be seen, the difference in the employment limit of Cr is not so large that sufficient precipitation does not occur. Therefore, it is preferable that aging treatment temperature is 400-700 degreeC.

The aging treatment time is preferably 30 minutes to 2 hours. When the aging treatment time is less than 30 minutes, sufficient precipitation strengthening effect is not obtained, and when 2 hours is exceeded, grains of Cr precipitates are too coarse and mechanical properties are deteriorated, which causes energy waste.

As described above, the method for manufacturing a contact material according to the present invention enables to have characteristics as a contact material superior to that manufactured by the conventional sintering method through a vacuum casting method and a post heat treatment process. According to another embodiment of the present invention, by adding a processing step between the vacuum casting and the post-heat treatment can have a more excellent contact material properties.

The processing is to process the ingot (ingot) produced by vacuum casting at a processing rate of 50 to 90% at a processing temperature of 800 to 1000 ℃ by one of the processing method of extrusion, drawing, forging. The extruding, drawing, and forging are all capable of producing long rods or tubes with uniform cross sections, and the vacuum ingots are processed by these three methods at the same processing cost in all directions. It is processed to shrink. 7 and 8 showing the texture photographs before and after the processing, Cr precipitates, which were distributed in a circular phase in the Cu substrate before processing, were arranged in a long line along the processing direction after processing. It can be seen that it has been changed into a laminated structure. When the Cr precipitate forms a layered form, electrons can be smoothly moved between the precipitate layers, thereby shortening the path of electrons, thereby increasing electrical and thermal conductivity. In addition, the layered Cr precipitates increase strength at room temperature and improve high temperature softening characteristics.

It is preferable that the temperature of the said processing process is 800-1000 degreeC. If the temperature is lower than 800 ° C., the ingot lacks the ductility, and large energy is required for processing. If the temperature is higher than 1000 ° C., the processing is easy, but the grains of Cu matrix are coarsened, which adversely affects the mechanical properties of the final product. In addition, although a processing ratio is defined as [(initial cross-sectional area) ^2- (cross-sectional area after processing) ² ] / (initial cross-sectional area) ² , it is preferable that it is 50 to 90%. If the processing cost is less than 50%, the Cr precipitates are not formed in an effective layered form. If the processing cost is more than 90%, a large processing energy is required in one processing, and large equipment must be used for this purpose. (Processing-heat treatment) increases the manufacturing cost.

The effect of the manufacturing method of the contact material for a vacuum circuit breaker according to the present invention configured as described above will be described with reference to specific examples.

(Example)

In order to compare the mechanical, electrical and thermal properties of the contact material produced by the manufacturing method according to the present invention and the contact material produced by the conventional sintering method was performed as follows. First, as a conventional example, a contact material prepared by sintering 25% Cr powder and 75% Cu powder by weight is prepared. As an embodiment according to the present invention, 5%, 15% and 25% Cr are contained in Cu. %, 35%, 50% and 75% mixed raw materials were cast in a vacuum atmosphere to prepare an ingot and extruded at an extrusion ratio of 70% at 800 ° C, followed by solution treatment at 1000 ° C for 1 hour, which was 400 to 700 ° C. Aging was carried out for 1 hour in the range to prepare a contact material. The results of measuring the mechanical, electrical, and thermal properties of these conventional examples and examples are shown in Table 2 below.

[Table 2]

division Fill rate (%) Hardness (HV) Strength (kg / mm ² ) Electrical Conductivity (IACS%) Thermal Conductivity (cal / cm ² / cm / ℃) High Temperature Softening Temperature (℃) Current breakdown count Gas content (PPM) Conventional example 98 108 ~ 112 40-50 40-45 0.3 ~ 0.4 460 20 400-800 Example 1 5% 100 110- 120 35-45 80-85 0.7 to 0.8 450 20-25 150 or less Example 2 15% 100 119 ~ 125 45-53 75-82 0.6-0.7 500 25-30 150 or less Example 3 25% 100 127 ~ 135 50-61 68-77 0.5 to 0.8 550 30-36 150 or less Example 4 35% 100 137 ~ 144 65-75 55-65 0.4-0.5 600 30-35 150 or less Example 5 50% 100 145 ~ 151 77-85 48-55 0.3 ~ 0.4 650 24 ~ 28 150 or less Example 6 75% 100 150 ~ 157 80-84 45-50 0.3 ~ 0.4 700 20-25 150 or less

As can be seen in Table 2 above, in the mechanical properties, the embodiment according to the present invention has high hardness and strength at room temperature compared with the conventional example, so that the permanent deformation is small and the wear resistance is increased as the number of breakers is increased. High softening temperature and high softening phenomena due to arcing were found to be small. In terms of electrical characteristics, the embodiment according to the present invention has excellent electrical conductivity, low contact resistance, and high electric current carrying capacity, so that the rated load current can be energized in the state of overheating, and the breaking performance is also excellent. This fact can be confirmed from the fact that the number of interruptions in the reference current 25KA is very high in 30 to 35 cycles compared to about 20 times in the conventional example. Finally, also in thermal properties, all the embodiments according to the present invention were found to be the same or higher than the prior art.

In order to examine the mechanical and electrical properties of the contact materials according to the present invention, the Cu 75% -Cr 25% raw material was vacuum cast and then extruded at an extrusion ratio of 70% at 800 ° C. for 1 hour at 1000 ° C. After the sieving treatment, the change in hardness (HV) and electrical conductivity (IACS%) was measured while aging for 1 hour in a temperature range of 200 to 800 ° C. The results are shown in FIGS. 9 and 10.

As shown in FIG. 9, the hardness showed a low value at 200 ° C., increased rapidly at 400 ° C. or higher, and showed the highest hardness at around 500 ° C. FIG. This is attributable to the effect of precipitation hardening, which occurs as the Cr particles dissolved in the solution are finely precipitated in the Cu matrix. However, at the temperature of 500 degreeC or more, a precipitate becomes coarse and hardness falls.

On the other hand, as shown in Figure 10, the electrical conductivity shows a low value at 200 ° C rapidly increases above 300 ° C to the highest electrical conductivity around 600 ° C, the electrical conductivity gradually decreases as the temperature increases. 9 and 10 described above are based on 25% Cr, but similar graphs are shown for 5%, 15%, 35%, 50%, and 75% Cr. In summary, in order to improve hardness and electrical conductivity in all composition ranges, it is preferable to perform aging treatment in the temperature range of 400 to 700 ° C.

As described above, according to the method of manufacturing a contact material for a vacuum circuit breaker according to the present invention, it is possible to manufacture a contact material having excellent mechanical, electrical, and thermal properties in comparison with a contact material manufactured by a conventional sintering method by a vacuum casting method and an aging treatment. have. In addition, it is possible to have more excellent characteristics by performing the processing before the aging treatment.

Claims (10)

A casting step of completely melting the raw materials of 20 to 95% Cu and 5 to 80% Cr by weight in a non-oxidizing atmosphere and then solidifying them to prepare an ingot; Solution ingot for 30 minutes to 2 hours at a temperature of 800 ~ 1070 ℃; And, Method for producing a contact material for a vacuum circuit breaker comprising the step of aging the solution-treated ingot (ingot) for 30 minutes to 2 hours at 400 ~ 700 ℃ temperature. The method of manufacturing a contact material for a vacuum circuit breaker according to claim 1, wherein the raw material of Cu and Cr further contains 0.1 to 3.0% by weight of Bi, Te, and Pb as solder alloy elements. The method according to claim 1 or 2, The casting step is a contact material for a vacuum circuit breaker comprising the step of processing the manufactured ingot at a processing rate of 50 to 90% at a processing temperature of 800 to 1000 ℃ by one of the processing method of extrusion, drawing, forging Manufacturing method. The method according to claim 1 or 2, The non-oxidizing atmosphere is a vacuum atmosphere manufacturing method of the contact material for the vacuum circuit breaker, characterized in that. The method of claim 3, Wherein the non-oxidizing atmosphere is a vacuum atmosphere manufacturing method of the contact material for a vacuum circuit breaker. 20% to 95% by weight of Cu and 5% to 80% of Cr are completely melted in a non-oxidizing atmosphere and then solidified to cast an ingot, and the cast ingot is 30 minutes to 2 minutes at a temperature of 800 to 1070 ° C. A contact material for a vacuum circuit breaker prepared by performing a solution treatment for a time and then aged for 30 minutes to 2 hours at a temperature of 400 to 700 ° C. The contact material for a vacuum circuit breaker according to claim 6, wherein the raw material of Cu and Cr further contains 0.1 to 3.0% by weight of Bi, Te, and Pb, which are solder alloy elements. The vacuum cut-off according to claim 6 or 7, wherein the cast ingot is processed at a processing ratio of 50 to 90% at a processing temperature of 800 to 1000 ° C by one of extrusion, drawing, and forging. Contact material for machine. The contact material for a vacuum circuit breaker according to claim 6 or 7, wherein the non-oxidizing atmosphere is a vacuum atmosphere. The contact material of claim 8, wherein the non-oxidizing atmosphere is a vacuum atmosphere.

Images