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A preparation method for optimizing copper-chromium contacts by adding ultra-fine-grained chromium phase

A technology of copper-chromium contacts and ultra-fine grains, which is applied in the directions of contacts, electrical components, electric switches, etc., can solve the problems of low cooling speed, large consumption of argon gas, and inapplicability to industrial mass production, etc., to reduce surface resistance, The effect of improving the quality of ball milling and reducing the resistance of ball milling

Active Publication Date: 2021-02-26
SHAANXI SIRUI ADVANCED MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Copper-chromium alloy contacts are the core components in the field of medium-voltage vacuum switches. After years of research, it is believed that the size of the chromium phase in the metallographic structure of copper-chromium alloy contacts can be reduced, which can greatly optimize the electrical and mechanical properties of the material. At present, the mainstream preparation process of copper-chromium alloy contacts is mainly divided into two types: smelting and powder metallurgy. The copper-chromium alloy contacts prepared by conventional vacuum induction melting are generally large in size due to the low cooling rate and the central area of ​​the contact. There is a large difference in the size of the chromium phase in the edge area. Even if a more advanced arc melting process is adopted to further increase the cooling rate, the size of the chromium phase remains at 20-50um, which is still relatively large compared to the size of the arc spot in the working environment , and due to the good mechanical properties of the as-cast structure, it is not conducive to the anti-welding resistance of the contact in service conditions, and the copper-chromium contact prepared by the mixed powder sintering process, although it solves the anti-welding performance of the contact , but limited by the original size of the chromium powder, the size of the chromium phase is coarser than that of the smelting process, which is not conducive to the electrical performance requirements of the contacts. Although the electrode induction melting gas atomization process can be used to prepare powders with extremely small chromium phases, It is used to prepare copper-chromium contacts by powder mixing and sintering, but the electrode induction melting gas atomization process has low efficiency and is not suitable for industrial mass production, and is limited by the process. The argon gas consumption in the gas atomization process is extremely high, resulting in huge production costs , thus greatly limiting the practical application of this process

Method used

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  • A preparation method for optimizing copper-chromium contacts by adding ultra-fine-grained chromium phase
  • A preparation method for optimizing copper-chromium contacts by adding ultra-fine-grained chromium phase
  • A preparation method for optimizing copper-chromium contacts by adding ultra-fine-grained chromium phase

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Experimental program
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Effect test

Embodiment 1

[0037] (1) Ingredients

[0038] Take Cu rods, Cr blocks, and conventional Cr powder as raw materials for use, wherein the mesh number of conventional Cr powder is -80+320;

[0039] (2) Vacuum induction melting

[0040] Put the above-mentioned Cu rods and Cr blocks into the ceramic crucible in the vacuum induction melting furnace according to the ratio of 19:1 by weight, and vacuumize until the vacuum degree reaches 9×10 -1 When Pa is below, heat the ceramic crucible with gradient heating power to melt the raw material. When Cu starts to melt, turn off the vacuum system and fill it with argon or other inert gas with a purity of 99.99% until the vacuum degree is -0.08MPa At the same time, preheat the tundish, keep the power at 7KW, wait until the molten metal is completely cleared, stir evenly, and keep the superheat at 100°C according to the composition of the molten metal, and prepare for atomization;

[0041] (3) Atomized powder making

[0042] Fill the vacuum smelting sys...

Embodiment 2

[0050] (1) Ingredients

[0051] Take Cu rods, Cr blocks, and conventional Cr powder as raw materials for use, wherein the mesh number of conventional Cr powder is -80+320;

[0052] (2) Vacuum induction melting

[0053] Put the above-mentioned Cu rods and Cr blocks into the ceramic crucible in the vacuum induction melting furnace according to the ratio of 10:1 by weight, and vacuumize until the vacuum degree reaches 9×10 -1 When Pa is below, heat the ceramic crucible with gradient heating power to melt the raw materials. When Cu starts to melt, turn off the vacuum system and fill it with argon or other inert gas with a purity of 99.99% until the vacuum degree is -0.03MPa At the same time, preheat the tundish, keep the power at 25KW, wait until the molten metal is completely cleared, stir evenly, and keep the superheat at 150°C according to the composition of the molten metal, and prepare for atomization;

[0054] (3) Atomized powder making

[0055] Fill the vacuum smelting s...

Embodiment 3

[0063] (1) Ingredients

[0064] Take Cu rods, Cr blocks, and conventional Cr powder as raw materials for use, wherein the mesh number of conventional Cr powder is -80+320;

[0065] (2) Vacuum induction melting

[0066] Put the above-mentioned Cu rods and Cr blocks into the ceramic crucible in the vacuum induction melting furnace according to the ratio of 4:1 by weight, and vacuumize until the vacuum degree reaches 9×10 -1 When Pa is below, the ceramic crucible is heated by gradient heating power to melt the raw materials. When Cu starts to melt, close the vacuum system and fill it with argon or other inert gas with a purity of 99.99% until the vacuum degree is 0.02MPa. At the same time, preheat the tundish, keep the power at 45KW, wait until the molten metal is completely cleared, stir evenly, and keep the superheat at 200°C according to the composition of the molten metal, and prepare for atomization;

[0067] (3) Atomized powder making

[0068] Fill the vacuum smelting sy...

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Abstract

The invention discloses a method for preparing a copper-chromium contact optimized by adding an ultra-fine-crystalline chromium phase, and belongs to the technical field of medium-voltage vacuum switches. Mainly include the following steps: (1) batching; (2) vacuum induction smelting; (3) atomization powder making; (4) powder mixing; (5) pressing and sintering; (6) mechanical processing; On the basis of atomization, copper-chromium alloy contacts are prepared by mixed powder sintering process, and copper-chromium alloy powder is prepared by vacuum induction gas atomization, which provides extremely fine chromium phase for the contacts. Then, by adding conventional chromium powder, solid The copper-chromium contact that meets the chromium content requirements is prepared by the phase sintering process. This contact not only avoids the excessive gas content caused by the pursuit of fine chromium particles in conventional production methods, but also the size of the chromium phase is much smaller than that of conventional chromium powder, which greatly optimizes the Contact performance: the copper-chromium contact prepared by the invention has low cost, excellent performance and is suitable for industrial mass production.

Description

technical field [0001] The invention belongs to the technical field of medium-voltage vacuum switches, and in particular relates to a method for preparing copper-chromium contacts optimized by adding ultra-fine-grained chromium phases. Background technique [0002] Copper-chromium alloy contacts are the core components in the field of medium-voltage vacuum switches. After years of research, it is believed that the size of the chromium phase in the metallographic structure of copper-chromium alloy contacts can be reduced, which can greatly optimize the electrical and mechanical properties of the material. At present, the mainstream preparation process of copper-chromium alloy contacts is mainly divided into two types: smelting and powder metallurgy. The copper-chromium alloy contacts prepared by conventional vacuum induction melting are generally large in size due to the low cooling rate and the central area of ​​the contact. There is a large difference in the size of the chr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C1/04H01H1/021H01H1/025B22F5/00
CPCB22F5/00B22F2998/10B22F2999/00C22C1/0425C22C1/045H01H1/021H01H1/025B22F2009/0848B22F9/082B22F1/0003B22F3/02B22F3/1007B22F2003/247B22F2201/20
Inventor 张石松刘凯王小军李鹏杨斌王文斌师晓云赵俊李刚
Owner SHAANXI SIRUI ADVANCED MATERIALS CO LTD