Copper-chromium alloy contact part and preparation method thereof

Abstract

The invention discloses a copper-chromium alloy contact part and a preparation method thereof, and belongs to the technical field of contact material processing. The preparation method comprises the steps that a substrate is installed, a cursor is printed on the substrate, and the cursor is consistent with the bottom face of a copper-chromium alloy contact target part in specification; bonding the connecting surface of the base body on the substrate to obtain a connected material; the connecting surface is matched with the cursor on the substrate; the connected material is fixed in a printing bin, infrared laser printing is conducted on the printing face of the base body according to preset laser additive manufacturing parameters, and a copper-chromium alloy contact part printing piece is obtained; and the copper-chromium alloy contact part printing piece is taken out to be subjected to solid solution heat treatment and separation, then groove position and inner hole machining is carried out, and a copper-chromium alloy contact target part is obtained. By means of the method, the high-strength and high-compactness copper-chromium alloy contact can be obtained.

Description

Technical Field

[0001] The present application belongs to the technical field of contact material processing, and specifically relates to a copper-chromium alloy contact part and a preparation method thereof. Background Art

[0002] Contact material is an electrical contact material used for switches, relays, electrical connections and electrical connectors. It is also called electrical contact material. It is generally divided into two types: contact material for strong electricity and contact material for weak electricity. The contact of the contactor is usually made of copper because copper has good electrical conductivity, thermal conductivity and ductility, which can meet the high requirements of the contactor in electrical control. Chromium is a rising star in contact materials. Chromium has strong corrosion resistance and high affinity for oxygen. During the opening and closing process of the vacuum switch, the evaporated film of chromium has an air absorption effect, which can ensure that the arc extinguishing chamber has a constant vacuum degree and prolong its service life. With the development of contact materials, copper and chromium alloy materials (CuCr) are widely used in vacuum switches, and CuCr materials are also used in SF6 circuit breakers.

[0003] In recent years, the manufacturing technology of high-chromium content contacts in CuCr materials has developed more rapidly. At the same time, the requirements for the use of higher voltage levels have gradually become concrete. For example, high-voltage copper-chromium contacts require higher chromium content, finer chromium particles, lower costs, smaller specifications, higher density, etc., to better meet application needs.

[0004] Currently, high-chromium content contacts can be prepared through 3D printing to solve the problems of large chromium particle size and low chromium content. However, the density of 3D printed high-chromium content contacts is still low, which is difficult to meet the use requirements, and there is a defect of large matrix loss. Summary of the invention

[0005] The purpose of the present application is to provide a copper-chromium alloy contact part and a preparation method thereof, so as to obtain a high-strength and high-density copper-chromium contact.

[0006] To achieve the above-mentioned purpose, the present application provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: Installing a substrate and printing a cursor on the substrate, wherein the cursor is consistent with the bottom surface specification of the copper-chromium alloy contact target part; Bonding the connection surface of the base body to the substrate to obtain a connected material; the connection surface is aligned with the cursor on the substrate; The connected material is fixed in a printing chamber, and infrared laser printing is performed on the printing surface of the substrate according to preset laser additive manufacturing parameters to obtain a copper-chromium alloy contact part printout; Taking out the copper-chromium alloy contact part printout, performing solution heat treatment and separation, and then processing the slot and inner hole to obtain the copper-chromium alloy contact target part; The shape of the base is a cylinder, the top surface of the base is a printing surface, and the bottom surface of the base is a connecting surface.

[0007] In the above scheme, the present application chooses to directly bond and fix the matrix on the substrate, and the bonding position of the matrix is ​​positioned by laser printing contour imprinting, which has very high accuracy and will not cause matrix loss due to grafting / compound eccentricity between the matrix and the substrate; and the cross-sectional shape of the matrix is ​​a cylinder with the same diameter as the bottom surface of the grafted contact. The high-chromium copper-chromium alloy contact parts produced in this way can save more than half of the raw material cost. The alloy structure of the copper-chromium alloy contact parts grafted and printed by the above scheme of the present application is fine and uniform, and the average particle size of the chromium particles is less than 5μm. The electrical conductivity of the copper-chromium alloy contact parts after heat treatment is comparable to that of the contact parts prepared by the traditional process, but its hardness is greatly improved, and at the same time, the wear resistance, corrosion resistance and breaking performance of the copper-chromium contact are improved. The entire preparation method is low-cost and simple and easy to promote, which is suitable for the production and processing of small and medium batches of copper-chromium contacts.

[0008] Preferably, before printing, the surface of the substrate is treated by sandblasting.

[0009] Preferably, the substrate is a universal printing plate with fixed size, the matrix is ​​a base for grafting or composite use with the same or similar specifications as the bottom surface of the copper-chromium alloy contact part, and the height of the matrix is ​​1 / 3 to 1 / 2 of the total height of the copper-chromium alloy contact part.

[0010] Preferably, the substrate is a T2 pure copper rod or a copper-chromium alloy rod; The mass percentage of chromium in the copper-chromium alloy rod is 0.1% to 1.5%; The cross-sectional diameter of the substrate is 20 mm to 200 mm, and the height of the substrate is 1 mm to 8 mm.

[0011] Preferably, a high temperature resistant liquid glue is used to bond the connection surface of the matrix to the base plate, and the high temperature resistant liquid glue is a two-phase mixed glue for multi-wire cutting.

[0012] Preferably, the raw material for infrared laser printing is a mixed powder formed by mixing aluminothermic chromium powder with a chromium content of 40wt% to 60wt% and the remainder of atomized copper powder, and the particle sizes of the copper powder and the chromium powder are both less than 200 meshes. In this solution, the addition of ultrafine chromium phase and vacuum induction atomization technology are used to prepare fine and evenly distributed chromium particles and copper particles, which can significantly improve the arc erosion resistance of the contact.

[0013] Preferably, the infrared laser printing comprises the following steps: Laying a layer of raw material powder on the building platform to obtain a powder layer; The raw material powder of the powder layer is melted by a 1000W infrared laser to combine the raw material powder with the printing surface of the substrate to obtain a single-layer printing structure; Repeatingly setting a powder layer on the surface of the single-layer printing structure, and then repeating the melting process to obtain a double-layer printing structure; Continue to set powder layers and repeat the melting process until the print is complete.

[0014] Preferably, the spot size of the infrared laser printing is 60 μm to 100 μm, and the spot spacing is 0.08 mm to 0.12 mm; The printing power of the infrared laser printing is 600W~900W, and the printing speed of the infrared laser printing is 800mm / s~1400mm / s; The thickness of the powder layer printed by the infrared laser is 0.03 mm to 0.06 mm.

[0015] In the above scheme, the use of high-power infrared laser additive manufacturing technology can effectively solve the problems of uniformity and density of high-chromium content contact materials, and is suitable for manufacturing contacts with complex shapes.

[0016] Preferably, the temperature of the solution heat treatment is 600° C. to 850° C., and the time of the solution heat treatment is 2 h to 6 h. By adopting this solution, the microstructure and performance of the copper-chromium alloy contact parts can be further optimized.

[0017] Preferably, the separation process includes: using wire cutting or manually breaking off the copper-chromium alloy contact parts.

[0018] Preferably, the processing of the groove and the inner hole includes: machining by machine or wire cutting.

[0019] To achieve the above-mentioned purpose, the present application also provides a copper-chromium alloy contact part, which is prepared according to the above-mentioned method for preparing the copper-chromium alloy contact part.

[0020] Preferably, the average particle size of chromium particles in the copper-chromium alloy contact part is less than 5 μm, and the density of the copper-chromium alloy contact part is above 99%.

[0021] In summary, this application has the following advantages: The present application provides a method for preparing copper-chromium alloy contact parts. In the process of fixing the substrate, the present application adopts bonding technology to replace the traditional hole-digging and inlaying technology, which effectively reduces the loss of substrate materials and reduces costs. In addition, the present application adopts the method of printing cursor positioning contours to achieve precise positioning of the substrate without reserving excess materials, thereby further reducing the cost of substrate raw materials and processing costs. The present application also combines the use of high-power infrared lasers with selective laser melting (SLM) for printing, which can greatly improve the density of copper-chromium contacts and make them meet the use standards of high voltage levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the preparation process of the copper-chromium alloy contact parts provided in the embodiment of the present application; Figure 2 This is a 100x metallographic photograph of the copper-chromium alloy contact part (CuCr0.5 / CuCr50) prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0023] One of the difficulties in the existing technology for preparing copper-chromium contacts with high chromium content is the density and uniformity of the material. Copper-chromium contacts with high chromium content are prone to high porosity and uneven structure during the sintering process, resulting in reduced mechanical strength and pressure resistance of the material. At the same time, the density difference between chromium particles and copper matrix is ​​large, and conventional powder mixing processes are also difficult to achieve uniform distribution, thus affecting the electrical properties of the contacts. For example, the instability of the traditional powder metallurgy manufacturing (powder mixing + compacting + sintering) technology will affect the uniformity of chromium distribution due to the instability of the powder mixing, and there will also be the problem of coarse chromium particles, resulting in low hardness of the produced contacts, which in turn leads to a shorter service life of the contacts.

[0024] The second difficulty lies in the sintering process. Contact materials with high chromium content are prone to component segregation and coarse grains during the sintering process, which affects the microstructure and performance of the material. For example, contacts prepared by vacuum consumable arc melting have a relatively uniform distribution of chromium particles, but the chromium particles are coarse, resulting in limited performance improvement of the contacts, and the material performance may also be unstable due to macroscopic pores, inclusions and other problems.

[0025] The third difficulty lies in the control of impurities. High-chromium contact materials have higher requirements for impurity content (such as oxygen, nitrogen, etc.). Traditional processes are difficult to effectively control impurities, thus affecting the arc erosion resistance of the contacts. At the same time, as a person skilled in the art, the inventor will also comprehensively consider the problems of long production cycle, high energy consumption, low material utilization rate, etc. in the existing technologies such as powder metallurgy, infiltration, vacuum consumable arc melting, etc.

[0026] The technical solution of this application is to combine the SLM grafting process with a high-power infrared laser to overcome the problems of uneven powder mixing, large chromium particles, large matrix loss and density in the prior art. The SLM grafting process of this application is: a composite process that uses a high-energy laser beam to simultaneously melt the surface of the substrate and the added material, and then achieves atomic-level mixing in the liquid state to form a metallurgical bonding interface. The strength of the composite material is equivalent to that of the substrate material.

[0027] The principles and features of the present application are described below in conjunction with the embodiments, and the examples are only used to explain the present application and are not used to limit the scope of the present application. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] like Figure 1 As shown, the present application provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: Installing a substrate and printing a cursor on the substrate, wherein the cursor is consistent with the bottom surface specification of the copper-chromium alloy contact target part; Bonding the connection surface of the base body to the substrate to obtain a connected material; the connection surface is aligned with the cursor on the substrate; The connected material is fixed in a printing chamber, and infrared laser printing is performed on the printing surface of the substrate according to preset laser additive manufacturing parameters to obtain a copper-chromium alloy contact part printout; Taking out the copper-chromium alloy contact part printout, performing solution heat treatment and separation, and then processing the slot and inner hole to obtain the copper-chromium alloy contact target part; The shape of the base is a cylinder, the top surface of the base is a printing surface, and the bottom surface of the base is a connecting surface.

[0029] It can be seen that the preparation process disclosed in the present application produces high-performance copper-chromium alloy contact parts through the precise positioning and bonding of the matrix and the substrate, SLM printing of the high chromium layer, adjustment of the solid solution structure, low-damage separation of parts and precision machining. Specifically, in the process of fixing the matrix, bonding is used instead of the traditional method of digging holes and inlaying the substrate, which reduces the loss of the substrate. Then, by printing a cursor on the substrate for precise positioning, the cursor is consistent with the contour of the copper-chromium alloy contact part, which can greatly reduce the cost of the matrix material and the cost of processing, and at the same time ensure that the misalignment of the grafting interface is small to avoid electric field distortion. The use of a high-power (1000W) infrared laser in combination with selective laser melting technology has greatly improved the density of the copper-chromium alloy contact parts, making their density reach more than 99%. This method can ultimately obtain low-cost, high-strength, high-density copper-chromium alloy contact parts, whose chromium content is as high as 40wt%~60wt%. The material is a composite additive printing structure of high-chromium copper-chromium alloy and other low-value pure copper (or copper-chromium alloy, chromium mass percentage is 0.5%~1.5%). The material has uniform organization and good density, which further improves the strength and anti-welding performance of the copper-chromium alloy contact. The copper-chromium alloy contact parts printed in this application can have a conductivity of 30%IACS~40%IACS and a hardness of 110HB~150HB after heat treatment, indicating that the method provided by this application not only improves the performance of the copper-chromium alloy contact itself, but also improves production efficiency, reduces production costs, and meets the application requirements under higher voltage levels and complex working conditions.

[0030] In summary, it can also be seen that the copper-chromium alloy contact parts of the present application are printed on the substrate, rather than on the conventional substrate, which is referred to as grafting printing. This printing method can enhance the bonding between the parts and the substrate. The substrate of the present application is fixed on the substrate by gluing, which replaces the conventional method of milling holes on the substrate and then inlaying the substrate. This method of fixing the substrate with glue is not only fast but also highly universal. The milling and inlaying methods will cause the substrate to frequently dig holes due to the variable specifications of the contacts, and cannot be used for printing, resulting in more material waste. The printing positioning method of the copper-chromium alloy contact and the substrate of the present application is: first layout according to the specifications of the bottom surface of the contact, then print the cursor mark on the substrate, and then use glue to align the substrate and the substrate with the contour and bond them. This alignment method has higher accuracy. In short, the present application ensures the coaxiality and yield rate of the grafting by the alignment method of first marking, then gluing, and finally printing. This application uses high-power infrared lasers in combination with SLM technology to print, and the organization is dense and uniform. Originally, 500W lasers could not print dense copper and copper alloy parts. In this application, the power can be increased to achieve a higher energy density, and then dense copper-chromium alloy contact parts can be printed. In addition, this application also reduces the internal stress, hardness or elasticity of the grafted printing through solution heat treatment, while improving the conductivity or electrical conductivity of the copper-chromium contact.

[0031] The following problems also exist in the prior art: When grafting or composite printing copper-chromium alloy, the main method of processing the substrate is grinding with a grinder. This method of directly printing after grinding can easily cause product defects such as warping and holes. Therefore, in some optional embodiments of the present application, before printing, the surface of the substrate is sandblasted to reduce the laser reflectivity, and then SLM is used in conjunction with infrared laser grafting printing to further improve the composite strength and avoid defects such as warping or holes.

[0032] In simple terms, the present application can provide a good foundation for subsequent printing through the pretreatment of the substrate, ensuring the bonding strength between the printed layer and the substrate; then by controlling the printing parameters and powder parameters, the formation of the molten pool and the density of the final structure are jointly affected; finally, the microstructure of the material is further optimized through heat treatment, thereby improving the overall performance.

[0033] In some optional embodiments of the present application, the substrate is a universal printing plate with fixed size, the matrix is ​​a base for grafting or composite use with the same or similar specifications as the bottom surface of the copper-chromium alloy contact part, and the height of the matrix is ​​1 / 3 to 1 / 2 of the total height of the copper-chromium alloy contact target part. It can be understood that the matrix can be a base for grafting with the same specifications as the bottom surface of the copper-chromium alloy contact target part, a base for grafting with similar specifications as the bottom surface of the copper-chromium alloy contact target part, a base for composite use with the same specifications as the bottom surface of the copper-chromium alloy contact target part, or a base for composite use with similar specifications as the bottom surface of the copper-chromium alloy contact target part.

[0034] In this application, the height of the substrate accounts for 1 / 3 to 1 / 2 of the total height of the copper-chromium alloy contact target part, which can ensure that the grafted printed part has good mechanical and electrical properties. Using T2 pure copper or copper-chromium alloy with low chromium content as the substrate can ensure the electrical and thermal conductivity of the contact. The specific range of diameter and height provides sufficient mechanical strength and is easy to produce and process.

[0035] In some optional embodiments of the present application, the substrate is a T2 pure copper rod or a copper-chromium alloy rod; The mass percentage of chromium in the copper-chromium alloy rod is 0.1% to 1.5%; The cross-sectional diameter of the substrate is 20 mm to 200 mm, and the height of the substrate is 1 mm to 8 mm. The size range of the substrate can be adapted to contacts of different specifications, such as from micro relays to high-voltage circuit breakers, and has strong versatility. Controlling the content of chromium and copper in the copper-chromium alloy rod can improve conductivity and interface compatibility, thereby avoiding mutual diffusion between the high-Cr substrate and the printed layer.

[0036] In some specific embodiments of the present application, the infrared laser printing comprises the following steps: Laying a layer of raw material powder on the building platform to obtain a powder layer; The raw material powder of the powder layer is melted by a 1000W infrared laser to combine the raw material powder with the printing surface of the substrate to obtain a single-layer printing structure; Repeatingly setting a powder layer on the surface of the single-layer printing structure, and then repeating the melting process to obtain a double-layer printing structure; Continue to set powder layers and repeat the melting process until the print is complete.

[0037] Simply put, the SLM used in this application is an additive manufacturing technology that builds three-dimensional objects by laying down powder materials layer by layer and using a high-energy laser to selectively melt the powder. After each layer of powder is melted, it will fuse with the solidified part of the previous layer to eventually form a complete part. During the SLM printing process, a very thin layer of powder material is first laid on the build platform. These powders are mixed powders of chromium powder and copper powder. The powder laying process requires precise control to ensure the uniformity and appropriate thickness of the powder layer. The infrared laser is one of the key components of the SLM printer. The laser it emits can be effectively absorbed by the metal powder, thereby achieving the melting of the powder.

[0038] The entire printing process includes: 1) Model slicing: Convert the 3D model into an STL file and slice it using software to generate the printing path for each layer.

[0039] 2) Laser melting: The infrared laser selectively scans the powder layer according to the slice data. The energy of the laser heats the powder to the melting point, causing it to melt and combine with other powder layers or substrates.

[0040] 3) Layer-by-layer construction: After the target layer is printed, the system will lay a new powder layer again and repeat the laser melting process until the entire model is printed and the copper-chromium alloy contact part is printed.

[0041] In some optional embodiments of the present application, a high temperature resistant liquid glue is used to bond the connecting surface of the matrix to the substrate, and the high temperature resistant liquid glue is a two-phase mixed glue for multi-wire cutting. In the present application, the high temperature resistant liquid glue is an epoxy resin glue, which has the characteristics of high strength, high adhesion, chemical corrosion resistance, low shrinkage after curing, and can well adapt to the stress and heat generated during multi-wire cutting. Usually, the high temperature resistant liquid glue is a two-component glue, that is, it is necessary to mix glue A and glue B in a certain proportion before use, and because the bonding strength after curing is very high, the bonding operation must be completed within a certain time after mixing glue A and glue B. The characteristic of epoxy resin glue is that it can be firmly bonded after being used at the position where bonding is required and waiting for 30 minutes. When the epoxy resin glue needs to be removed, it is only necessary to flush the bonding position with boiling water. It can be seen that the epoxy resin glue has a temporary fixing force and can meet the requirements of the vibration environment of printing. In this application, the purpose can be achieved by using conventional commercially available materials, such as the epoxy resin AB glue of Juli (Dongguan) New Materials Technology, the HT-528 280-degree high-temperature resistant epoxy AB glue of Dongguan Haoteng Adhesive Products, the DZ8180 epoxy resin glue AB glue of Dongzhen Technology, and the like.

[0042] In some optional embodiments of the present application, the raw material for infrared laser printing is a mixed powder formed by mixing aluminothermic chromium powder with a chromium content of 40wt%~60wt% (for example, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, etc.) and the remainder of aerosolized copper powder, and the particle sizes of the copper powder and the chromium powder are both less than 200 mesh.

[0043] In the present application, the mixed powder can be a mixed powder prepared by recycling copper-chromium contact waste, which further reduces the production cost. Then, the grafting printing is carried out by the manufacturing method of laser powder additive, which reduces the cost of copper-chromium materials and improves the printing quality, material utilization rate and yield rate. Among them, the aluminothermic method is a metal thermal reduction method, which is usually used to produce high-purity metal powder. The chromium powder here refers to a powder containing 40wt%~60wt% chromium produced by the aluminothermic method. Atomization is a technology for producing metal powder. The metal vapor is condensed into powder by rapid cooling. The copper powder here is used as the remainder (that is, another part of the raw material besides the chromium powder). Atomization and aluminothermic method are both conventional technical means in this field, and will not be repeated here.

[0044] In some optional embodiments of the present application, the spot size of the infrared laser printing is 60 μm to 100 μm, and the spot spacing is 0.08 mm to 0.12 mm; The printing power of the infrared laser printing is 600W~900W, and the printing speed of the infrared laser printing is 800mm / s~1400mm / s; The thickness of the powder layer printed by the infrared laser is 0.03 mm to 0.06 mm.

[0045] In the scheme of the present application, the SLM powder spreading method and the infrared laser can accurately control the printing process, and the selection of printing parameters helps to achieve good mechanical properties and precision. Appropriate printing power, speed and layer thickness can ensure printing quality and efficiency. Impact beyond the parameter range: Printing power that is too high will cause over-melting of powder or damage to the substrate, while printing power that is too low may lead to insufficient bonding between printed layers. Printing speed that is too fast will lead to uneven printing, while printing speed that is too slow will reduce printing efficiency. If the thickness of the powder layer is too large, the printing accuracy will be reduced, while if it is too small, poor bonding between printed layers may occur, affecting the printing results. In the preparation method of the present application, the heat-affected zone is limited to the surface layer of the substrate by precisely controlling the infrared laser printing parameters, so that overall annealing can be avoided. High-strength bonding and service reliability of the interface are guaranteed from the physical metallurgical and process control levels, solving the problems of easy annealing and cracking of traditional welding.

[0046] In some optional embodiments of the present application, the temperature of the solution heat treatment is 600°C to 850°C (for example, 600°C, 650°C, 700°C, 750°C, 800°C and 850°C, etc.), and the time of the solution heat treatment is 2h to 6h. Heat treatment can improve the mechanical properties and stability of the printed part, and the use of a vacuum heat treatment furnace can reduce oxidation, thereby improving the quality of the contact. Too low a temperature may result in poor heat treatment effect, while too high a temperature may cause the material to overheat or deform. In the present application, the temperature range of 600°C to 850°C can not only eliminate residual stress and inhibit grain growth, but also promote Cr solid solution and enhance the potential for subsequent aging strengthening. If the solution heat treatment time is too long, Cr may diffuse excessively into the matrix and form a Cr-poor zone at the interface.

[0047] In some optional embodiments of the present application, the separation process includes: using wire cutting or manually breaking off the printed copper-chromium alloy contact parts.

[0048] In some optional embodiments of the present application, the processing of the groove and the inner hole includes: using machine processing or wire cutting.

[0049] In some optional embodiments of the present application, the slots and inner holes need to be cleaned after processing before packaging. The cleaning process needs to thoroughly remove residual powder and glue. Incomplete cleaning may affect the electrical performance of the contacts.

[0050] In the second aspect, based on a general technical concept, the present application also discloses a copper-chromium alloy contact part, which is prepared by the above-mentioned method for preparing the copper-chromium alloy contact part. The average particle size of the chromium particles in the copper-chromium alloy contact part is less than 5 μm, and the density of the copper-chromium alloy contact part is more than 99%.

[0051] The above technical solution of the present application is described in detail below in conjunction with specific embodiments.

[0052] Example 1 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: Select a copper-chromium alloy rod with a chromium mass percentage of 0.5% as the substrate, use a saw to cut it into 1 / 2 of the height of the target copper-chromium alloy contact part, and then use sandblasting and a surface grinder to grind the double end surfaces (i.e., the printing surface and the connecting surface, the same below) until they are smooth.

[0053] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0054] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 40wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0055] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0056] Among them, the printed spot size is 60μm, and the spot spacing is 0.10mm; The printing power is 650W, the printing speed is 1000mm / s, and the powder layer thickness is 0.04mm.

[0057] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 700°C, and the high temperature time is 4h.

[0058] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0059] Example 2 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 0.5% was selected as the substrate, and cut into 1 / 3 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double-end surfaces were polished to be smooth using sandblasting and a surface grinder.

[0060] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0061] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 50wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0062] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0063] Among them, the printed spot size is 100μm, the spot spacing is 0.12mm; the printing power is 720W, the printing speed is 1000mm / s; the powder layer thickness is 0.04mm.

[0064] S5: Take out the printed copper-chromium alloy contact part obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 780°C, and the high temperature time is 4h.

[0065] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are manually broken off, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated. The 100x metallographic photo of the obtained material is as follows: Figure 2 As shown, it can be seen that the structure of the copper-chromium part in the final copper-chromium alloy contact part is dense and uniform, and the chromium particles in the metallographic phase are basically in the range of 2μm~5μm.

[0066] Example 3 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 0.5% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0067] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0068] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 60wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0069] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0070] Among them, the spot size is 60μm, the spot spacing is 0.08mm; the printing power is 830W, the printing speed is 1000mm / s; the powder layer thickness is 0.04mm.

[0071] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 850°C, and the high temperature time is 4h.

[0072] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0073] Example 4 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 1.2% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0074] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0075] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 40wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0076] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0077] Among them, the spot size is 80μm, the spot spacing is 0.08mm; the printing power is 650W, the printing speed is 1000mm / s; the powder layer thickness is 0.04mm.

[0078] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 700°C, and the high temperature time is 4h.

[0079] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0080] Example 5 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 1.2% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0081] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0082] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 50wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0083] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0084] Among them, the spot size is 90μm, the spot spacing is 0.08mm; the printing power is 720W, the printing speed is 1000mm / s; the powder layer thickness is 0.04mm.

[0085] S5: Take out the printed copper-chromium alloy contact part obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 780°C, and the high temperature time is 4h.

[0086] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0087] Example 6 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 1.2% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0088] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0089] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 60wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0090] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0091] Among them, the printed spot size is 100μm, the spot spacing is 0.12mm; the printing power is 830W, the printing speed is 1000mm / s; the powder layer thickness is 0.04mm.

[0092] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 850°C, and the high temperature time is 4h.

[0093] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0094] The copper-chromium alloy contact parts prepared in Examples 1 to 6 were subjected to hardness (Brinell hardness, ASTM E10) and electrical conductivity tests (international annealed copper standard, ASTM F390). The test methods were all conventional means in the art. The test results are shown in Table 1.

[0095]

[0096] In Table 1, CuCr0.5 / CuCr40 means that the mass percentage of chromium in the matrix is ​​0.5%, the raw material for printing is a mixed powder, and the mass percentage of chromium in the mixed powder is 40%; CuCr0.5 / CuCr50 means that the mass percentage of chromium in the matrix is ​​0.5%, the raw material for printing is a mixed powder, and the mass percentage of chromium in the mixed powder is 50%. Similarly, CuCr1.2 / CuCr60 in Example 6 means that the mass percentage of chromium in the matrix is ​​1.2%, the raw material for printing is a mixed powder, and the mass percentage of chromium in the mixed powder is 60%.

[0097] As can be seen from Table 1, the copper-chromium alloy contact parts obtained by the method provided by this application have a dense and uniform structure of the copper-chromium part, the particle size of the chromium particles in the metallographic phase is basically in the range of 2μm~5μm, the hardness of the printed parts after heat treatment is above HB120, the electrical conductivity is about 10% higher than that of the parts prepared by the traditional process, and the density of the parts is above 99%. In addition, the copper-chromium alloy contact parts obtained by this application also have good arc extinguishing performance, breaking performance and high wear resistance, meeting the application requirements under higher voltage levels and complex working conditions.

[0098] Example 7 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 1.5% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0099] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0100] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 55wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0101] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0102] Among them, the printed spot size is 90μm, and the spot spacing is 0.10mm; The printing power is 700W, the printing speed is 1000mm / s, and the powder layer thickness is 0.04mm.

[0103] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 620°C, and the high temperature time is 5.5h.

[0104] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0105] Example 8 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 1.2% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to smoothness using sandblasting and a surface grinder.

[0106] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0107] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 42wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0108] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0109] Among them, the printed spot size is 75μm, and the spot spacing is 0.09mm; The printing power is 600W, the printing speed is 1200mm / s, and the powder layer thickness is 0.05mm.

[0110] S5: Take out the copper-chromium alloy contact part printout obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 825°C, and the high temperature time is 4.5h.

[0111] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0112] Example 9 This embodiment provides a method for preparing a copper-chromium alloy contact part, comprising the following steps: S1: A copper-chromium alloy rod with a chromium mass percentage of 0.25% was selected as the substrate, and cut into 1 / 2 of the height of the target copper-chromium alloy contact part using a sawing machine, and then the double end surfaces were polished to be smooth using sandblasting and a surface grinder.

[0113] S2: First, print a cursor mark on the surface of the substrate according to the bottom surface specifications of the copper-chromium contact, and then apply multi-line cutting two-phase mixed glue on the connecting surface of the substrate, and bond it to the substrate. When gluing, pay attention to the overlap of the outer contour of the substrate with the outer contour of the laser marking.

[0114] S3: A mixed powder prepared by mixing aluminothermic chromium powder with a chromium content of 50wt% and the rest of aerosolized copper powder is selected as a raw material for grafting printing, wherein the particle sizes of the chromium powder and the copper powder are both sieved through a 200-mesh sieve.

[0115] S4: placing the bonded substrate and base plate in the printing chamber of the infrared laser, and performing infrared laser printing on the printing surface of the substrate using the SLM powder spreading method.

[0116] Among them, the printed spot size is 95μm, and the spot spacing is 0.11mm; The printing power is 900W, the printing speed is 850mm / s, and the powder layer thickness is 0.04mm.

[0117] S5: Take out the printed copper-chromium alloy contact part obtained after printing, place it in a vacuum heat treatment furnace for solution heat treatment, and obtain the copper-chromium alloy contact target part; wherein, the use temperature is set to 650°C, and the high temperature time is 5h.

[0118] S6: After the solution heat treatment, the copper-chromium alloy contact target parts are removed by wire cutting, and then the slots and inner holes are processed by wire cutting, and finally cleaned and encapsulated.

[0119] Although the specific implementation methods of this application are described in detail, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for preparing a copper-chromium alloy contact part, characterized in that: The following steps are involved: Installing a substrate and printing a cursor on the substrate, wherein the cursor is consistent with the bottom surface specification of the copper-chromium alloy contact target part; Bonding the connection surface of the base body to the substrate to obtain a connected material; The connection surface matches the cursor on the substrate; The connected material is fixed in a printing chamber, and infrared laser printing is performed on the printing surface of the substrate according to preset laser additive manufacturing parameters to obtain a copper-chromium alloy contact part printout; Taking out the copper-chromium alloy contact part printout, performing solution heat treatment and separation, and then processing the slot and inner hole to obtain the copper-chromium alloy contact target part; The shape of the base is a cylinder, the top surface of the base is a printing surface, and the bottom surface of the base is a connecting surface.

2. The method for preparing the copper-chromium alloy contact part according to claim 1, characterized in that: The substrate is a T2 pure copper rod or a copper-chromium alloy rod, and the height of the substrate is 1 / 3 to 1 / 2 of the copper-chromium alloy contact target part; The mass percentage of chromium in the copper-chromium alloy rod is 0.1% to 1.5%.

3. The method for preparing the copper-chromium alloy contact part according to claim 1 or 2, characterized in that: The cross-sectional diameter of the substrate is 20 mm to 200 mm, and the height of the substrate is 1 mm to 8 mm.

4. The method for preparing the copper-chromium alloy contact part according to claim 1, characterized in that: The connecting surface of the matrix is ​​bonded to the base plate by using a high temperature resistant liquid glue, and the high temperature resistant liquid glue is a two-phase mixed glue for multi-wire cutting.

5. The method for preparing the copper-chromium alloy contact part according to claim 1, characterized in that: The raw material for infrared laser printing is a mixed powder formed by mixing aluminothermic chromium powder with a chromium content of 40wt% to 60wt% and the remainder of aerosolized copper powder, and the particle sizes of the copper powder and the chromium powder are both less than 200 meshes.

6. The method for preparing the copper-chromium alloy contact part according to claim 1 or 5, characterized in that: The infrared laser printing comprises the following steps: Laying a layer of raw material powder on the building platform to obtain a powder layer; The raw material powder of the powder layer is melted by a 1000W infrared laser to combine the raw material powder with the printing surface of the substrate to obtain a single-layer printing structure; Repeatingly setting a powder layer on the surface of the single-layer printing structure, and then repeating the melting process to obtain a double-layer printing structure; Continue to set powder layers and repeat the melting process until the print is complete.

7. The method for preparing the copper-chromium alloy contact part according to claim 6, characterized in that: The spot size of the infrared laser printing is 60 μm to 100 μm, and the spot spacing is 0.08 mm to 0.12 mm; The printing power of the infrared laser printing is 600W~900W, and the printing speed of the infrared laser printing is 800mm / s~1400mm / s; The thickness of the powder layer printed by the infrared laser is 0.03 mm to 0.06 mm.

8. The method for preparing the copper-chromium alloy contact part according to claim 1, characterized in that: The temperature of the solution heat treatment is 600° C. to 850° C., and the time of the solution heat treatment is 2 h to 6 h.

9. A copper-chromium alloy contact part, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. The copper-chromium alloy contact part according to claim 9, characterized in that: The average particle size of chromium particles in the copper-chromium alloy contact part is less than 5 μm, and the density of the copper-chromium alloy contact part is above 99%.

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