JP2009129856A - Contact point material for vacuum valve, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact point material for a vacuum valve in which a pulverization of an arc-proof component in a conductive component is improved and breaking characteristics and a voltage resisting property are improved. <P>SOLUTION: The contact point material for the vacuum valve is provided with a pair of contact points 12, 14 which are attachable and detachable, and a surface of a base material composing the contact points 12, 14 composed of a conductive component at least out of the conductive component and an arc-proof component undergoes a friction padding treatment in which a padding material of which the arc-proof component particles are dispersed in a conductive component matrix is rotated to form a padded layer in which the arc-proof component particles are pulverized. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a contact material for a vacuum valve that can improve a breaking characteristic, a withstand voltage characteristic, and the like, and a manufacturing method thereof.

  The application range of the vacuum switchgear is being expanded due to its environmental harmony, and application to the high voltage region has been attempted. As a contact material of a vacuum valve, a composite material in which arc resistant component particles such as Cr and Mo are dispersed in a matrix of a conductive component is generally used (for example, refer to Patent Document 1).

  When a contact material is used in a high voltage region, the dielectric breakdown mechanism between the contacts includes the separation of particles such as arc resistant components. In particular, in a brittle arc resistant component such as Cr, the arc resistant component particles exposed on the contact surface are crushed by opening and closing, and fine particles that cause dielectric breakdown are generated. For this reason, the arc resistant component particles are atomized and finely dispersed in the conductive component matrix so as not to be exposed on the contact surface.

  As a fine dispersion method, arc-resistant component particles and conductive component particles are manufactured by a sintering method, a conductive component dissolved between arc-resistant component particles is infiltrated, or conductive For example, there is a method in which both the heat resistant component and the arc resistant component are dissolved and rapidly cooled to crystallize the arc resistant component finely in the conductive component.

On the other hand, a technique is known in which friction stir processing is performed on the surface of a metal member, surface modification is performed by friction heat and a stirring action of a rotating body, and mechanical strength such as toughness is improved (for example, see Patent Document 2). . However, the metal structure on the surface of the metal member is merely changed from a rough state to a dense state, and does not finely disperse different component particles such as a conductive component and an arc resistance component as described above.
JP 2006-233298 A (pages 4-5, FIG. 1) JP 2004-68681 A (pages 3 to 4, FIG. 1)

  In the above conventional contact material, in addition to the withstand voltage characteristics, energization characteristics and interruption characteristics are required, and Cr, Mo, etc. are selected as main arc resistance components. However, these arc-resistant components are relatively easily oxidized and are difficult to manufacture by a sintering method using fine particles as raw materials. For this reason, an arc melting method or a vacuum melting method is used to refine the arc-resistant component. However, there is a limit to the refinement of dispersion by these production methods, and a contact material and a production method thereof that can further refine the arc resistance component have been desired.

  The present invention has been made to solve the above-described problems, and provides a contact material for a vacuum valve and a method for manufacturing the same that can reduce the arc resistance component and improve the breaking characteristics and the withstand voltage characteristics. Objective.

  In order to achieve the above object, the contact material for a vacuum valve of the present invention is a contact material for a vacuum valve, and is provided on the surface of a base material composed of at least a conductive component among a conductive component and an arc resistant component. A build-up layer is formed by applying a friction build-up process of rotating a build-up material in which arc-resistant component particles are dispersed in a conductive component matrix.

  According to the present invention, the friction build-up process is performed with the cladding material in which the arc resistance component is dispersed in the conductive component, and the overlay layer is formed on the surface of the contact, so that the arc resistance component is fine. Can be dispersed to improve the withstand voltage characteristic and the cutoff characteristic.

  Embodiments of the present invention will be described below with reference to the drawings.

  A vacuum valve contact material according to an embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view showing a configuration of a vacuum valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a configuration of one contact of a vacuum valve according to an embodiment of the present invention, and FIG. It is a figure explaining the manufacturing method of the contact for vacuum valves which concerns on an Example.

  As shown in FIG. 1, a lid 3 is sealed at both ends of the vacuum insulating container 1 via a sealing fitting 2, and a pair of electrodes 6, 7 are arranged at opposite ends of the current-carrying shafts 4, 5. Is arranged. The upper electrode 6 is a fixed electrode, and the lower electrode 7 is a movable electrode. A telescopic bellows 8 is attached to the energizing shaft 5 so that the energizing shaft 5 can be moved in the axial direction while keeping the inside of the vacuum insulating container 1 in a vacuum. A metal arc shield 9 is provided above the bellows 8, and a metal cylindrical arc shield 10 is provided so as to surround the electrodes 6 and 7. Further, as shown in FIG. 2, the end of the current-carrying shaft 5 is fixed to the movable electrode 7 by a brazing part 11, and the contact 12 is also fixed by a brazing part 13. The fixed side contact 14 is also fixed in the same manner as the movable side.

  A method of manufacturing such contacts 12 and 14 will be described with reference to FIG.

  As shown in FIG. 3, the build-up layer 17 is pressed against the surface of a base material 15 such as Cu to be the contact points 12 and 14 with a predetermined surface pressure while rotating the build-up material 16 in which the arc-resistant component is dispersed. To form. In this friction build-up process, the base material 15 is translated at a speed of about 500 mm / min while the build-up material 16 is rotated at about 1000 rpm by a rotating device (not shown). Plastic flow occurs at the contact surface between the build-up material 16 and the base material 15, and when it is cooled, a build-up layer 17 in which the arc-resistant component is refined is formed on the surface of the substrate 15. The spraying of the shielding gas 18 using argon gas was performed so that a gas having a predetermined pressure hits the friction surface.

  In the process in which the build-up material 16 flows on the surface of the base material 15, the arc-resistant component particles dispersed in the conductive component matrix are deformed and pulverized. Since the pulverization is performed while being included in the conductive component, the chance of the arc-resistant component being oxidized or nitrided by the surrounding atmosphere is reduced. Therefore, it is possible to obtain a contact material having a fine structure with a low gas content.

  Here, the arc resistant component particles in the cladding layer 17 are contained in the base material 15 and the cladding material 16. It will be a thing. When the end surface orthogonal to the axial direction of the build-up material 16 is parallel to the surface of the base material 15, the arc-resistant component particles increase in frictional area and are easily miniaturized.

  In the production of the contacts 12 and 14, the build-up layer 17 may be formed on the base material 15 having a predetermined shape, and the build-up layer 17 is formed on the base material 15 having an area larger than the base layer 15. May be processed. In particular, the latter is preferable because the built-up layer 17 is uniformly formed up to the ends of the contacts 12 and 14.

Evaluation of the built-up layer 17 manufactured by such a method is as follows.
1) Oxygen content It measured by the infrared absorption method.
2) Average interparticle distance A plurality of auxiliary lines were drawn vertically and horizontally in the cross-sectional structure photograph, the interparticle distance of the arc resistant component was measured, and the average value was obtained.
3) Thickness and hardness Thickness was measured from a cross-sectional structure photograph. Further, the ratio between the Vickers hardness of the build-up material 16 and the Vickers hardness of the base material 15 was determined.
4) Dielectric withstand voltage characteristics after opening and closing with no load After incorporating into a vacuum valve for evaluating electrical characteristics, performing no load opening and closing 100 times, the gap length was set to 8 mm, and the dielectric breakdown voltage was determined by the voltage rise method. The result of Example 1 to be described later was set as a reference (1.0), other examples and comparative examples were shown as relative values, and 0.9 or more was regarded as acceptable.
5) Dielectric strength characteristics after throwing-off welding For Examples 8 and 9 and Comparative Example 3 to be described later, an arc is generated at the time of charging and welding is performed, and the state is mechanically pulled off, and the withstand voltage is the same as in Section 4. The characteristics were determined.
6) Breaking characteristics Regarding Example 10 and Comparative Example 4 to be described later, the gap length is 8 mm, and a synthesis test is performed under a 12 kV application condition, and re-ignition does not occur when the current is gradually increased stepwise. The upper limit breaking current value was determined.
These results will be described with reference to Table 1.

(Example 1 and Comparative Example 1)
In Example 1, the Cu-15 wt% Cr base material 15 manufactured by the melting method was subjected to friction build-up processing using the build-up material 16 manufactured by the sintering method with the same composition, and the contacts 12 and 14 were connected. Manufactured. In Comparative Example 1, the contacts 12 and 14 were manufactured using Cu-25 wt% Cr manufactured by a melting method. As a result, in Example 1, as shown by the circles in FIG. 3, the Cr particles are refined and uniformly dispersed in the built-up layer 17, and the average interparticle distance is 0.5 μm, which is shorter than Comparative Example 1. became. In addition, the oxygen content was 500 ppm, which was higher than that of Comparative Example 1 of 100 ppm, but the withstand voltage characteristic was higher than that of Comparative Example 1. The withstand voltage value of the first embodiment is a reference.

(Examples 2 and 3)
In Example 2, the Cu-15 wt% Cr base material 15 produced by the infiltration method was subjected to a friction build-up process using the build-up material 16 produced by the sintering method with the same composition, and the contacts 12, 14. Manufactured. In Example 3, the base material 15 of Cu-25 wt% Cr manufactured by the sintering method was subjected to friction build-up processing using the build-up material 16 manufactured by the melting method with the same composition, and the contacts 12 and 14 were formed. Manufactured. As a result, the Vickers hardness of the build-up material 16 became harder in Example 3, but in both cases, the Cr particles were refined and good voltage resistance characteristics were obtained.

(Examples 4 and 5 and Comparative Example 2)
The build-up material 16 which made the base material 15 Cu and changed content of Cr with 25, 50, and 75 wt% was manufactured by the sintering method. In any case, the withstand voltage characteristics were good because the Cr content of the cladding material 16 was higher than that of the base material 15. However, in Comparative Example 2, the Vickers hardness of the build-up material 16 was 2.2 times that of the base material 15, and the build-up layer 17 in which Cr particles were uniformly dispersed was not formed. Since the variation in the distance between the particles was large and it was not in a state suitable for the contacts 12 and 14, it was indicated that the overlay layer 17 was not formed in the table. For this reason, the ratio of the Vickers hardness of the build-up material 16 is preferably twice or less that of the base material 15.

(Examples 6 and 7 and Comparative Example 3)
The base material 15 was made into Cu-25 wt% Cr manufactured by the sintering method, and the cladding material 16 in which the Cr content was changed to 5, 35, and 50 wt% was manufactured by the sintering method. The ratio of Vickers hardness was around 1. In Examples 6 and 7, the interparticle distance was 0.2 to 0.3 μm, and the withstand voltage characteristics were good. However, in Example 3, the Cr content of the build-up material 16 was small, the interparticle distance was increased, and the withstand voltage characteristics were insufficient.

(Examples 8 and 9 and Comparative Example 4)
Build-up with thickness changed to 0.5, 1, and 3 mm by using the build-up material 16 produced by the sintering method with the same composition on the base material 15 of Cu-25 wt% Cr produced by the melting method Layer 17 was formed. The thickness was controlled by pressing the build-up material 16 and the moving speed of the base material 15. In any case, the withstand voltage characteristic after no-load switching was good. However, the withstand voltage characteristics after throwing-off welding were lower than those of Examples 8 and 9 in Comparative Example 4 in which the overlay layer 17 had a thickness of 0.5 mm. Assuming that Example 8 is 1.0, it is 1.1 times in Example 9 and 0.5 times in Comparative Example 4. For this reason, in the case where welding can occur, it is preferable to set the thickness of the build-up layer 17 to 1 mm or more so that it can withstand the input welding pull-out force. The input welding pull-out force is generally several hundred kgf.

(Example 10 and Comparative Example 5)
The overlaying material 16 produced by the sintering method with the same composition was used for the base material 15 of Cu-25 wt% Cr produced by the melting method, and the presence or absence of spraying of argon gas was evaluated. In any case, the withstand voltage characteristic after no-load switching was good. However, in the cutoff characteristics, the cutoff current value of Example 10 using the shield gas 18 was higher than that of Comparative Example 5. Assuming that Example 10 is 1.0, Comparative Example 5 is 0.7 times. For this reason, the friction build-up process using the shield gas 18 can reduce the oxygen content, and can improve the cutoff characteristics as well as the withstand voltage characteristics. Further, the cooling can be promoted by spraying the shield gas 18.

(Examples 11 and 12)
In Example 11, the friction build-up process was performed on the Cu-20 wt% Mo base material 15 produced by the melting method using the build-up material 16 produced by the sintering method with the same composition. In Example 12, friction build-up treatment was performed on the base material 15 of Cu-10 wt% Mo-12.5 wt% Cr manufactured by the melting method using the build-up material 16 manufactured by the sintering method with the same composition. did. In any case, the withstand voltage characteristics are good, and a Cu—Mo alloy or a Cu—Mo—Cr alloy can be used as the contact material in addition to the Cu—Cr alloy.

According to the contact material for a vacuum valve of the above embodiment, the overlaying layer 17 is formed by applying the friction overlaying process for rotating the overlaying material 16 on the surface of the base material 15 constituting the contacts 12 and 14. The arc-resistant component is pulverized, refined and dispersed, the amount of gas becomes low, and the withstand voltage characteristic and the interruption characteristic can be improved.

Sectional drawing which shows the structure of the vacuum valve which concerns on the Example of this invention. Sectional drawing which shows the structure of one contact of the vacuum valve which concerns on the Example of this invention. The figure explaining the manufacturing method of the contact for vacuum valves concerning the example of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum insulation container 2 Sealing metal fitting 3 Cover body 4, 5 Current supply shaft 6, 7 Electrode 8 Bellows 9, 10 Arc shield 11, 13 Brazing part 12, 14 Contact 15 Base material 16 Overlay material 17 Overlay layer 18 Shield gas

Claims (7)

A contact material for a vacuum valve,
On the surface of the base material composed of at least the conductive component of the conductive component and the arc resistant component,
Friction overlaying is performed by rotating a cladding material in which arc-resistant component particles are dispersed in a conductive component matrix,
A contact material for a vacuum valve, characterized by forming a built-up layer. The conductive component is Cu;
The contact material for a vacuum valve according to claim 1, wherein at least one of Cr and Mo is used as the arc resistance component.   The contact material for a vacuum valve according to claim 1 or 2, wherein the build-up layer has a thickness that can withstand a welding pull-off force. On the surface of the base material composed of at least the conductive component of the conductive component and the arc resistant component,
While rotating while pressing the cladding material in which arc-resistant component particles are dispersed in the conductive component matrix, the base material is moved to cause plastic flow,
A method for producing a contact material for a vacuum valve, characterized in that a build-up layer in which at least the arc-resistant component particles are refined is formed.   The build-up material is Cu-Cr, Cu-Mo-Cr, or Cu-Mo, and is manufactured by any one of a sintering method and a melting method. Manufacturing method of contact material for vacuum valve.   The said base material is either Cu, Cu-Cr, Cu-Mo, and it manufactured by the method of any one of the sintering method, the infiltration method, and the melt | dissolution method, The Claim 4 or Claim 5 characterized by the above-mentioned. The manufacturing method of the contact material for vacuum valves as described in 2 ..   The method for producing a contact material for a vacuum valve according to any one of claims 4 to 6, wherein the plastic flow of the substrate surface is performed in a shielding gas atmosphere.

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