Processing method of copper-chromium shielding cylinder for vacuum interrupter

Abstract

The application discloses a processing method of a copper-chromium shielding cylinder for a vacuum arc-extinguishing chamber, and comprises the following steps: S1, copper-chromium forging ingot; S2, rough turning of an outer circle and sawing of a material head; S3, multi-wire cutting processing of a blank, S3-1, rod material solidification, and S3-2, cutting processing; S4, automatic spinning; and S5, finishing of a product. Compared with a traditional copper-chromium shielding cylinder formed by extrusion, the copper-chromium shielding cylinder has the advantages of high utilization rate, fast forming speed, good surface quality, high precision, no influence of the size and specifications of the shielding cylinder, suitability for various products, simple change of types, and suitability for batch production and manufacturing.

Description

Technical Field

[0001] This invention relates to the field of metal shielding cylinder processing technology, specifically to a processing method for a copper-chromium shielding cylinder for a vacuum interrupter. Background Technology

[0002] The structure of a vacuum interrupter typically includes components such as electrodes, fuses, contacts, a metal shielding cylinder, and a ceramic shell. Among these, the metal shielding cylinder plays a crucial role, primarily in the following ways: 1. Preventing or mitigating the contamination of the inner wall of the insulating shell by metal vapor and droplets generated during arcing, thereby avoiding a decrease in the insulation strength of the vacuum interrupter shell and flashover. 2. Improving the electric field distribution inside the vacuum interrupter, which helps reduce local field strength and promotes miniaturization, especially for high-voltage vacuum interrupters. 3. Condensing arc products and absorbing some arc energy, which is beneficial for restoring the dielectric strength of the arc gap.

[0003] Shielding cylinders can be made of materials such as oxygen-free copper, stainless steel, electrical pure iron, or copper-chromium alloys. As vacuum interrupters continue to develop towards higher voltage levels, copper-chromium shielding cylinders are receiving increasing market attention, primarily due to their high strength, high conductivity, heat dissipation, and strong isolation and guiding arc-extinguishing capabilities, ensuring the long-term reliable and stable operation of vacuum interrupters. The preparation methods for copper-chromium shielding cylinder materials are relatively mature, generally including powder metallurgy and vacuum melting methods. However, due to the density issues of powder metallurgy valve shielding cylinders, their strength is inferior to that of vacuum-melted shielding cylinders, especially limiting their application in high-voltage fields. The end-market prefers copper-chromium shielding cylinder materials produced by vacuum melting. Currently, the processing method for preparing copper-chromium shielding cylinder blanks using vacuum melting mainly relies on extrusion (hot extrusion), resulting in low material utilization, low production efficiency, high equipment investment, high energy consumption, and high noise levels. Furthermore, the processing of large-size shielding cylinders is limited; currently, large-size shielding cylinders cannot be mass-produced by extrusion blanks, mainly due to high initial equipment investment costs, high mold costs, complex shape changeovers, and low material utilization. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for processing a copper-chromium shielding cylinder for a vacuum interrupter.

[0005] The technical solution of this invention is: a method for processing a copper-chromium shielding cylinder for a vacuum interrupter, comprising the following steps:

[0006] S1, copper-chromium forging ingot

[0007] CuCr1-CrCr30 materials with a Brinell hardness of 50-120HB, prepared by vacuum melting, were used as raw materials for forging to obtain copper-chromium forging ingots of the target size.

[0008] S2, Rough turning of outer diameter, sawing of material head

[0009] The surface of the copper-chromium forging ingot is rough-turned to 1-4mm, and then 2-6cm is removed from both ends of the ingot using a saw to obtain the copper-chromium contact bar to be cut. This step is mainly to remove the defective parts at both ends of the bar to ensure the parallelism of the blank during the next multi-wire cutting.

[0010] S3, Multi-wire EDM machining of blanks

[0011] S3-1, Rod Curing

[0012] The number of copper-chromium contact rods to be cut is adjusted according to the diameter of the rods, and they are fixed to a transparent glass plate with UV-curing adhesive. Then, a UV curing lamp is used for curing, with a curing time of 1-15 minutes. The UV-curing adhesive has a tensile strength of 13-15 MPa, a shear strength of 16-18 MPa, and a coating width of 5-20 mm. The light transmittance of the transparent glass plate is >93%.

[0013] S3-2, Cutting and Processing

[0014] Set the cutting thickness standard value and tolerance according to the program, fix the transparent glass plate to the worktable of the diamond wire multi-wire cutting machine, raise the worktable so that the starting cutting surface of the copper-chromium contact bar to be cut is close to the diamond wire, start the cutting program to cut, and spray coolant on the surface of the copper-chromium contact bar to be cut at a rate of 3-5mL / s. When the diamond wire cuts 2-6mm to the surface of the transparent glass plate, stop the machine to complete the cutting and obtain a copper-chromium flat blank.

[0015] S4, Automatic Spinning

[0016] Prepare a spinning die (φ76.8mm×85mm) and a top die (φ70mm×80mm). Then, vacuum heat the copper-chromium flat blank obtained in step S3-2 to 400-900℃ and hold it for 5-90 minutes until the vacuum degree reaches 1×10⁻⁶. -2 Pa, after the copper-chromium flat blank is taken out and fixed on the mold of the spinning machine, the machine tool is driven with the spindle speed of 50-1500 r / min and the tail force ≤10kN, so that the copper-chromium flat blank rotates with the machine spindle. At this time, the spinning cutter applies pressure to the copper-chromium flat blank with a feed rate of 5-50 mil / cutter, so that it produces plastic deformation. The spinning time is 3-8min, so that the local plastic deformation of the copper-chromium flat blank extends to the entire surface and adheres tightly to the mold, thus producing the copper-chromium shielding cylinder part;

[0017] S5, Finished Products

[0018] After the copper-chromium shielding cylinder parts are polished, they are processed into finished products using automated processes to obtain copper-chromium shielding cylinders for vacuum interrupters.

[0019] Description: Compared with the traditional hot extrusion method, the automatic spinning method of this invention enables continuous forming, making full use of raw materials and improving material utilization. At the same time, the automatic spinning method ensures uniform stress, and heat treatment in a vacuum environment before spinning can avoid product material defects and further improve the production efficiency of copper-chromium shielding cylinders.

[0020] Furthermore, in the rough turning of the outer diameter in step S2, the depth of cut is 1-3 mm, the spindle speed is 500-800 r / min, and the feed rate is 0.1-0.4 mm / r.

[0021] Note: The above outer diameter parameters enable the physical properties of the contact bar material to reach a better state, ultimately resulting in better performance of the copper-chromium shielding cylinder.

[0022] Further, before step S3-1, the copper-chromium contact bar material to be cut undergoes surface treatment; the surface treatment method is as follows:

[0023] Weigh out 15-20% methanol, 10-15% epoxy resin, 5-7% benzene rings, and the balance deionized water by mass percentage, and mix them thoroughly to prepare a treatment solution. Prepare the treatment solution according to the weight-to-volume ratio of the copper-chromium contact bar to be cut to the treatment solution of 1.3-1.5 kg: 300-330 mL, and divide it into 2-4 equal portions. Take one portion of the treatment solution and spray it onto the dried surface of the copper-chromium contact bar to be cut at a rate of 5-8 mL / s. After spraying, let it stand for 30-50 seconds, and then irradiate it with an intensity of 10-12 W / cm². 2 The surface of the copper-chromium contact bar is irradiated with microwave for 2-4 minutes. After the initial treatment, another portion of the treatment solution is taken and sprayed onto the surface of the copper-chromium contact bar to be cut. The settling time after spraying is increased by 10-15 seconds each time, and then the irradiation intensity is adjusted and the treatment continues for 1-2 minutes. This cycle is repeated until the treatment solution is completely sprayed. The spraying rate of the treatment solution is increased by 1-1.5 mL / s each time, and the irradiation intensity is increased by 8-10 W / cm² each time. 2 Improve;

[0024] Note: The resin-containing treatment solution provides good adhesion and protection to copper-chromium contacts, offering excellent insulation and corrosion resistance, thereby extending the contact's service life. During the thermal spraying process, the molten epoxy resin reacts with the surface of the copper-chromium contact to form chemical bonds, further enhancing the adhesion between the coating and the substrate. The methanol content mentioned above can dilute and dissolve the treatment solution, helping to control the density and porosity of the coating, thereby improving its protective performance. The addition of benzene rings improves the lubrication effect during copper-chromium contact wire cutting, while also increasing the adhesion between the contact wire and the contact surface, reducing vibration and movement, and improving cutting stability. Furthermore, benzene rings can simultaneously enhance the wear resistance of UV-cured adhesive, thereby further improving the adhesion between the copper-chromium contact and the UV-cured adhesive, and increasing cutting efficiency. Allowing the coating to stand before microwave treatment allows the treatment solution to penetrate more fully, enhancing adhesion, improving wear resistance and durability, and improving the electrical and thermal conductivity of the contact. At the same time, it can also avoid the micro-defects or cracks formed on the material surface by direct microwave treatment, which would affect corrosion resistance.

[0025] Furthermore, the mixing method involves mixing methanol, epoxy resin, and deionized water at a speed of 400-450 r / min for 20-30 min, then dividing the benzene ring into 4-6 equal parts, and spraying it every 2-4 min during the mixing process until the mixing is complete;

[0026] Note: Spraying benzene rings in batches allows them to mix better with other components, further improving the adhesion between the wire and the contact surface, reducing wear on the wire EDM tool, and extending the tool's service life.

[0027] Furthermore, the copper-chromium contact bar material to be cut is pretreated by means of: immersing the copper-chromium contact bar material to be cut in a nitric acid solution with a mass concentration of 3-4% for 15-25 minutes, rinsing it with deionized water 1-3 times after removal, and finally drying it in a drying oven at a temperature of 50-55℃ for 25-35 minutes for later use.

[0028] Explanation: Soaking the copper-chromium contact bar material to be cut in the above-mentioned mass concentration of nitric acid solution can activate the surface of the copper-chromium contact, making it more reactive. Then, when it is mixed with benzene rings, the binder component in the benzene rings can form chemical bonds with the activated surface, further enhancing the adhesion between the coating and the substrate, thereby fixing the copper-chromium contact and the UV shadowless adhesive.

[0029] Further, in step S3-1, the dimensions of the glass plate are 450mm × 200mm × 10-30mm, and the relationship between the number of copper-chromium contact bars to be cut and their diameter is as follows: if the diameter D of the copper-chromium contact bars to be cut is ≤ 40mm, then the number of bars is 2-5; if the diameter D of the copper-chromium contact bars to be cut is ≤ 60mm, then the number of bars is 1-3; if the diameter D of the copper-chromium contact bars to be cut is > 60mm, then the number of bars is 1-2.

[0030] Note: The above settings allow for a certain gap between each bar, ensuring process stability during wire EDM, reducing the likelihood of wire skipping, and further improving cutting efficiency.

[0031] Furthermore, in step S3-2, the process parameters set during the cutting process are: wire tension of 10-80N, wire speed of diamond wire of 500-900m / min, wire amount of diamond wire of 300-600m / cycle, and table lifting speed of 1.2-8.0mm / min.

[0032] Note: Insufficient tension can lead to instability and breakage of the diamond wire, while excessive tension may cause wire breakage or equipment damage. Too fast a winding / unwinding speed can result in uneven cutting, while too slow a speed will reduce production efficiency. Improper control of the winding / unwinding amount may cause uneven cutting surfaces or overcutting, leading to a decrease in shielding cylinder performance. Too fast an ascent speed can result in a rough cutting surface, while too slow a speed will prolong processing time and reduce production efficiency. Parameters within the above range can produce shielding cylinders with better surface quality and more stable performance.

[0033] Furthermore, in step S3-2, the diamond wire is a diamond wire with a specification D = 0.10-0.60 mm; the coolant is a water-soluble cutting fluid with a preparation ratio of 1-10 wt%.

[0034] Note: Diamond wire is selected because it has extremely high hardness and wear resistance, enabling it to quickly cut various hard materials and improve production efficiency; the water-soluble cutting fluid is commercially available and is used to cool the heat between the diamond wire and the bar stock, ensuring the stability of the cutting process.

[0035] Furthermore, in step S4, the feed rate of the rotary cutter is adjusted according to the spindle speed and is divided into four stages:

[0036] The first stage: the initial spindle speed is 50 r / min, and then it is increased to 300-320 r / min at a rate of 160 r / min. During this process, the feed rate of the rotary cutter is 45-50 microns / cutter.

[0037] Second stage: When the spindle speed reaches 300-320 r / min, the spindle speed is increased to 800-820 r / min at a rate of 280 r / min. During this process, the rotary cutter is reduced from 45-50 mils / cut to 25-30 mils / cut at a rate of 8-10 mils / cut per minute and then maintained.

[0038] The third stage: When the spindle speed reaches 800-820 r / min, the spindle speed is increased to 1480-1500 r / min at a rate of 350 r / min. During this process, the rotary cutter is reduced from 25-30 mils / cut to 15-20 mils / cut at a rate of 5-7 mils / cut per minute and then maintained.

[0039] Fourth stage: When the spindle speed reaches 1480-1500 r / min, the spindle speed is reduced to 50 r / min at a rate of 420 r / min. During this period, the feed rate of the spinning cutter is maintained at 5-10 microns / cut until the spinning process is completed.

[0040] Explanation: The feed rate of the rotary cutter is adjusted by combining the spindle speed and the feed rate of the rotary cutter. By adjusting the feed rate of the rotary cutter according to the spindle speed in four stages, the material flow and forming can be better controlled while promoting faster material flow and redistribution. The above parameters can effectively improve the performance of the shielding cylinder without ensuring that the material is not over-compressed or stretched.

[0041] Furthermore, after the second and third stages, finishing treatments are performed respectively. The finishing treatment method is as follows: place the copper-chromium shielding cylinder into the electrolytic cell, then add grinding stones and polishing liquid with a concentration of 3-5%, turn on the rectifier, and adjust the current in the electrolytic cell to 0.5-1A / dm³. 2 The voltage is 15-20V. After polishing for 3-5 hours, remove the tube and clean the copper-chromium shielding tube with water 3-5 times. Let it air dry naturally in a dry environment.

[0042] Note: This method can make the surface smoother and flatter without changing the shape and size of the blank. Furthermore, the natural drying method can avoid defects caused by heat treatment, and further improve the corrosion resistance and conductivity of the copper-chromium shielding cylinder.

[0043] The beneficial effects of this invention are:

[0044] (1) Compared with traditional extruded copper-chromium shielding cylinders, the present invention has the advantages of high material utilization, fast forming speed, good surface quality, high precision, no influence of shielding cylinder size and specifications, applicable to a variety of products, simple changeover, and suitable for mass production.

[0045] (2) The present invention uses the combination of spindle speed and rotary cutter feed to adjust the rotary cutter feed. By adjusting the rotary cutter feed according to the spindle speed in four stages, the material can be better controlled while promoting faster material flow and redistribution. The electrochemical polishing operation after the second and third stages can further optimize the material distribution and further improve the performance of the copper-chromium shielding cylinder.

[0046] (3) The copper-chromium pretreatment of the copper-chromium contacts in this invention with a resin-containing treatment solution can give the copper-chromium contacts better adhesion and protection, as well as provide good insulation and corrosion resistance, thereby improving the performance of the copper-chromium shielding cylinder and further extending the service life of the shielding cylinder. In addition, the combined effect of methanol and benzene ring can effectively increase the adhesion between the contact wire and the contact surface, reduce the occurrence of shaking and movement during the cutting process, improve the cutting stability, and further improve the preparation efficiency of the copper-chromium shielding cylinder. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the present invention;

[0048] Figure 2 This is the finished copper-chromium shielding cylinder obtained in Embodiment 1 of the present invention. Detailed Implementation

[0049] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0050] Example 1: A method for processing a copper-chromium shielding cylinder for a vacuum interrupter, comprising the following steps:

[0051] S1, copper-chromium forging ingot

[0052] CuCr10 material with a Brinell hardness of 85HB, prepared by vacuum melting, was used as raw material for forging to obtain copper-chromium forging ingots of the target size.

[0053] S2, Rough turning of outer diameter, sawing of material head

[0054] The surface of the copper-chromium forging ingot is rough-turned to 3mm, and then 4cm is removed from the top and bottom ends of the ingot using a saw to obtain the copper-chromium contact bar to be cut; during the rough turning process in step S2, the depth of cut is 2mm, the spindle speed is 650r / min, and the feed rate is 0.3mm / r.

[0055] S3, Multi-wire EDM machining of blanks

[0056] The copper-chromium contact bar material to be cut is pretreated by immersing it in a 3.5% nitric acid solution for 20 minutes, rinsing it twice with deionized water, and finally drying it in a drying oven at 53°C for 30 minutes for later use.

[0057] The copper-chromium contact bar stock to be cut undergoes surface treatment; the surface treatment method is as follows:

[0058] According to the mass percentage, 18% methanol, 13% epoxy resin, 6% benzene ring, and the balance deionized water were weighed and mixed evenly to prepare a treatment solution. The treatment solution was prepared according to a weight-to-volume ratio of 1.4 kg of copper-chromium contact bar to be cut to 315 mL of treatment solution, and divided into three equal portions. One portion of the treatment solution was taken and sprayed onto the dried surface of the copper-chromium contact bar to be cut at a rate of 7 mL / s. After spraying, it was allowed to stand for 40 seconds. However The subsequent irradiation intensity was 11 W / cm. 2 The surface of the copper-chromium contact bar was irradiated with microwave for 3 minutes. After the initial treatment, another portion of the treatment solution was taken and sprayed onto the surface of the copper-chromium contact bar to be cut. The settling time after spraying was increased by 13 seconds each time, and then the irradiation intensity was adjusted and the treatment continued for 1.5 minutes. This cycle was repeated until the treatment solution was completely sprayed. The spraying rate of the treatment solution was increased by 1.2 mL / s each time, and the irradiation intensity was increased by 9 W / cm² each time. 2 Improve;

[0059] The mixing method involves mixing methanol, epoxy resin, and deionized water at a speed of 425 r / min for 25 min, then dividing the benzene ring into 5 equal parts and spraying them every 3 min during the mixing process until the mixing is complete.

[0060] S3-1, Rod Curing

[0061] The number of copper-chromium contact bars to be cut is adjusted according to the diameter of the copper-chromium contact bars to be cut, and they are fixed on a transparent glass plate with UV shadowless adhesive. Then, they are cured with a UV curing lamp for 8 minutes. The tensile strength of the UV shadowless adhesive is 14MPa, the shear strength is 17MPa, and the application width is 12mm. The light transmittance of the transparent glass plate is >93%.

[0062] In this embodiment, the dimensions of the glass plate are 450mm×200mm×20mm, the diameter D of the copper-chromium contact bar to be cut is 150mm, and the number of bars is 2.

[0063] S3-2, Cutting and Processing

[0064] According to the program setting of the standard value and tolerance for cutting thickness, the transparent glass plate is fixed to the worktable of the diamond wire multi-wire cutting machine. The worktable is raised so that the starting cutting surface of the copper-chromium contact bar to be cut is close to the diamond wire. The cutting program is started to cut. At the same time, coolant is sprayed onto the surface of the copper-chromium contact bar to be cut at a rate of 4mL / s. When the diamond wire cuts 4mm to the surface of the transparent glass plate, the machine is stopped to complete the cutting and obtain a copper-chromium flat blank.

[0065] In step S3-2, the process parameters set during the cutting process are as follows: wire tension is 45N, diamond wire winding speed is 700m / min, diamond wire winding amount is 450m / cycle, and table rise speed is 4.6mm / min; the diamond wire is diamond wire with specification D=0.4mm; the coolant is water-soluble cutting fluid with a preparation ratio of 5wt%.

[0066] S4, Automatic Spinning

[0067] Prepare a spinning die (φ76.8mm×85mm) and a top die (φ70mm×80mm). Then, vacuum heat the copper-chromium flat blank obtained in step S3-2 to 600℃ and hold it for 45 minutes until the vacuum degree reaches 1×10⁻⁶. -2 Pa, after the copper-chromium flat blank is taken out and fixed on the mold of the spinning machine, the machine tool is driven with a spindle speed of 800 r / min and a tail force of 10 kN, so that the copper-chromium flat blank rotates with the machine spindle. At this time, the spinning cutter applies pressure to the copper-chromium flat blank with a feed rate of 30 mil / cut, so as to produce plastic deformation. The spinning time is 6 minutes, so that the local plastic deformation of the copper-chromium flat blank extends to the entire surface and adheres tightly to the mold, thus producing the copper-chromium shielding cylinder part;

[0068] S5, Finished Products

[0069] After surface polishing, the copper-chromium shielding cylinder parts are processed into finished products using automated machining to obtain copper-chromium shielding cylinders for vacuum interrupters.

[0070] Example 2: Unlike Example 1, in step S1, CuCr1 material with a Brinell hardness of 50HB prepared by vacuum melting is used as raw material for forging to obtain copper-chromium forging ingots of the target size.

[0071] Example 3: Unlike Example 1, in step S1, CrCr30 material with a Brinell hardness of 120HB prepared by vacuum melting is used as raw material for forging to obtain copper-chromium forging ingots of the target size.

[0072] Example 4: Unlike Example 1, in step S2, the surface of the copper-chromium forging ingot is rough-turned to 1mm, and then 2cm is cut off from the top and bottom ends of the forging ingot using a saw to obtain the copper-chromium contact bar material to be cut.

[0073] Example 5: Unlike Example 1, in step S2, the surface of the copper-chromium forging ingot is rough-turned to a diameter of 4mm, and then 6cm is cut off from the top and bottom ends of the forging ingot using a saw to obtain the copper-chromium contact bar material to be cut.

[0074] Example 6: Unlike Example 1, in step S2, the roughing depth of cut is 1 mm, the spindle speed is 500 r / min, and the feed rate is 0.1 mm / r.

[0075] Example 7: Unlike Example 1, in step S2, the roughing depth of cut is 3mm, the spindle speed is 800r / min, and the feed rate is 0.4mm / r.

[0076] Example 8: Unlike Example 1, before step S3-1, the pretreatment method is as follows: the copper-chromium contact bar material to be cut is soaked in a 3% nitric acid solution for 25 minutes, then rinsed once with deionized water, and finally dried in a drying oven at 50°C for 35 minutes for later use.

[0077] Example 9: Unlike Example 1, before step S3-1, the pretreatment method is as follows: the copper-chromium contact bar material to be cut is immersed in a 4% nitric acid solution for 15 minutes, then rinsed with deionized water 3 times, and finally dried in a drying oven at 55°C for 25 minutes for later use.

[0078] Example 10: Unlike Example 1, before step S3-1, 15% methanol, 10% epoxy resin, 5% benzene ring and the remainder deionized water were weighed and mixed evenly to prepare the treatment solution.

[0079] Example 11: Unlike Example 1, before step S3-1, 20% methanol, 15% epoxy resin, 7% benzene ring and the remainder deionized water were weighed and mixed evenly to prepare the treatment solution.

[0080] Example 12: Unlike Example 1, before step S3-1, a treatment solution was prepared according to a weight-to-volume ratio of 1.3 kg of copper-chromium contact bar material to be cut to 300 mL of treatment solution, and divided into two equal portions. One portion of the treatment solution was taken and sprayed onto the dried surface of the copper-chromium contact bar material to be cut at a rate of 5 mL / s. After spraying, it was allowed to stand for 30 seconds, and then irradiated with an intensity of 10 W / cm². 2The surface of the copper-chromium contact bar was irradiated with microwave for 2 minutes. After the treatment, another portion of the treatment solution was sprayed onto the surface of the copper-chromium contact bar to be cut at a rate of 6 mL / s. The settling time after spraying was increased by 10 seconds each time, and then the irradiation intensity was adjusted to 18 W / cm². 2 And continue processing for 1 minute.

[0081] Example 13: Unlike Example 1, before step S3-1, a treatment solution was prepared according to a weight-to-volume ratio of 1.5 kg of copper-chromium contact bar material to be cut to 330 mL of treatment solution, and divided into 4 equal portions. One portion of the treatment solution was taken and sprayed onto the surface of the dried copper-chromium contact bar material to be cut at a rate of 8 mL / s. After spraying, it was allowed to stand for 50 seconds. However The subsequent irradiation intensity was 12 W / cm. 2 The surface of the copper-chromium contact bar was irradiated with microwave for 4 minutes. After the initial treatment, another portion of the treatment solution was taken and sprayed onto the surface of the copper-chromium contact bar to be cut. The settling time after spraying was increased by 15 seconds each time, and then the irradiation intensity was adjusted and the treatment continued for 2 minutes. This cycle was repeated until the treatment solution was completely sprayed. The spraying rate of the treatment solution was increased by 1.5 mL / s each time, and the irradiation intensity was increased by 10 W / cm² each time. 2 Improve it.

[0082] Example 14: Unlike Example 1, before step S3-1, the mixing method is to mix methanol, epoxy resin and deionized water at a speed of 400 r / min for 30 min, and then divide the benzene ring into 4 equal parts, spraying once every 4 min during the mixing process until the mixing is completed.

[0083] Example 15: Unlike Example 1, before step S3-1, the mixing method is to mix methanol, epoxy resin and deionized water at a speed of 450 r / min for 20 min, and then divide the benzene ring into 6 equal parts, spraying once every 2 min during the mixing process until the mixing is completed.

[0084] Example 16: Unlike Example 1, in step S3-1, the curing time is 1 min; the tensile strength of the UV shadowless adhesive is 15 MPa, the shear strength is 18 MPa, and the application width is 20 mm.

[0085] Example 17: Unlike Example 1, in step S3-1, the curing time is 15 min; the tensile strength of the UV shadowless adhesive is 13 MPa, the shear strength is 16 MPa, and the application width is 5 mm.

[0086] Example 18: Unlike Example 1, the diameter D of the copper-chromium contact bar to be cut is 60mm, and the number of bars is 3.

[0087] Example 19: Unlike Example 1, the diameter D of the copper-chromium contact bar to be cut is 40mm, and the number of bars is 4.

[0088] Example 20: Unlike Example 1, in step S3-2, coolant is sprayed onto the surface of the copper-chromium contact bar to be cut at a rate of 3 mL / s. When the diamond wire cut reaches 6 mm on the surface of the transparent glass plate, the machine is stopped to complete the cutting and a copper-chromium flat blank is obtained.

[0089] Example 21: Unlike Example 1, in step S3-2, coolant is sprayed onto the surface of the copper-chromium contact bar to be cut at a rate of 5 mL / s. When the diamond wire cut reaches 2 mm on the surface of the transparent glass plate, the machine is stopped to complete the cutting and a copper-chromium flat blank is obtained.

[0090] Example 22: Unlike Example 1, in step S3-2, the process parameters set during the cutting process are as follows: wire tension is 10N, diamond wire winding speed is 500m / min, diamond wire winding amount is 300m / cycle, and table rising speed is 1.2mm / min.

[0091] Example 23: Unlike Example 1, in step S3-2, the process parameters set during the cutting process are as follows: wire tension is 80N, diamond wire winding speed is 900m / min, diamond wire winding amount is 600m / cycle, and table rising speed is 8.0mm / min.

[0092] Example 24: Unlike Example 1, in step S4, the copper-chromium flat blank prepared in step S3-2 is vacuum heated to 400°C and held for 90 minutes until the vacuum degree reaches 1×10⁻⁶. -2 Pa, after the copper-chromium flat blank is taken out and fixed on the mold of the spinning machine, the machine tool is driven with a spindle speed of 50 r / min and a tail force of 10 kN, so that the copper-chromium flat blank rotates with the machine tool spindle. At this time, the spinning cutter applies pressure to the copper-chromium flat blank with a feed rate of 5 mil / cutter, so as to produce plastic deformation. The spinning time is 8 min.

[0093] Example 25: Unlike Example 1, in step S4, the copper-chromium flat blank prepared in step S3-2 is vacuum heated to 900°C and held for 5 minutes until the vacuum degree reaches 1×10⁻⁶. -2 Pa, after the copper-chromium flat blank is taken out and fixed on the mold of the spinning machine, the machine tool is driven with a spindle speed of 1500 r / min and a tail force of 10 kN, so that the copper-chromium flat blank rotates with the machine spindle. At this time, the spinning cutter applies pressure to the copper-chromium flat blank with a feed rate of 50 mil / cutter, so as to produce plastic deformation. The spinning time is 3 min.

[0094] Example 26: Unlike Example 1, in step S4, the feed rate of the rotary cutter is adjusted according to the spindle speed and is divided into four stages: First stage: The initial spindle speed is 50 r / min, and then it is increased to 300 r / min at a rate of 160 r / min. During this process, the feed rate of the rotary cutter is 45 filaments / cutter.

[0095] Second stage: When the spindle speed reaches 300 r / min, the spindle speed is increased to 800 r / min at a rate of 280 r / min. During this process, the rotary cutter is reduced from 45 mils / cut to 25 mils / cut at a rate of 8 mils / cut per minute and then maintained.

[0096] The third stage: When the spindle speed reaches 800 r / min, the spindle speed is increased to 1480 r / min at a rate of 350 r / min. During this process, the rotary cutter is reduced from 25 mils / cut to 15 mils / cut at a rate of 5 mils / cut per minute and then maintained.

[0097] Fourth stage: When the spindle speed reaches 1480 r / min, the spindle speed is reduced to 50 r / min at a rate of 420 r / min. During this period, the feed rate of the rotary cutter is maintained at 5 microns / cutter until the spinning process is completed.

[0098] Example 27: Unlike Example 1, in step S4, the feed rate of the rotary cutter is adjusted according to the spindle speed and is divided into four stages: First stage: The initial spindle speed is 50 r / min, and then it is increased to 310 r / min at a rate of 160 r / min. During this process, the feed rate of the rotary cutter is 47 filaments / cutter.

[0099] Second stage: When the spindle speed reaches 310 r / min, the spindle speed is increased to 810 r / min at a rate of 280 r / min. During this process, the rotary cutter is reduced from 47 mils / cutter to 27 mils / cutter at a rate of 9 mils / cutter per minute and then maintained.

[0100] The third stage: When the spindle speed reaches 810 r / min, the spindle speed is increased to 1490 r / min at a rate of 350 r / min. During this process, the rotary cutter is reduced from 27 mils / cutter to 17 mils / cutter at a rate of 6 mils / cutter per minute and then maintained.

[0101] Fourth stage: When the spindle speed reaches 1490 r / min, the spindle speed is reduced to 50 r / min at a rate of 420 r / min. During this period, the feed rate of the rotary cutter is maintained at 7 microns / cutter until the spinning process is completed.

[0102] Example 28: Unlike Example 1, in step S4, the feed rate of the rotary cutter is adjusted according to the spindle speed and is divided into four stages: First stage: The initial spindle speed is 50 r / min, and then it is increased to 320 r / min at a rate of 160 r / min. During this process, the feed rate of the rotary cutter is 50 filaments / cutter.

[0103] Second stage: When the spindle speed reaches 320 r / min, the spindle speed is increased to 820 r / min at a rate of 280 r / min. During this process, the rotary cutter is reduced from 50 mils / cut to 30 mils / cut at a rate of 10 mils / cut per minute and then maintained.

[0104] The third stage: When the spindle speed reaches 820 r / min, the spindle speed is increased to 1500 r / min at a rate of 350 r / min. During this process, the rotary cutter is reduced from 30 mils / cut to 20 mils / cut at a rate of 7 mils / cut per minute and then maintained.

[0105] Fourth stage: When the spindle speed reaches 1500 r / min, the spindle speed is reduced to 50 r / min at a rate of 420 r / min. During this period, the feed rate of the rotary cutter is maintained at 10 microns / cutter until the spinning process is completed.

[0106] Example 29: Unlike Example 27, finishing treatments were performed after the second and third stages. The finishing treatment method was as follows: the copper-chromium shielding cylinder was placed in the electrolytic cell, then grinding stones and a 3% polishing solution were added, the rectifier was turned on, and the current in the electrolytic cell was adjusted to 0.5A / dm. 2 The voltage is 15V. After polishing for 5 hours, remove the tube and clean the copper-chromium shielding tube three times with clean water. Let it air dry naturally in a dry environment.

[0107] Example 30: Unlike Example 27, finishing treatments were performed after the second and third stages. The finishing treatment method was as follows: the copper-chromium shielding cylinder was placed in the electrolytic cell, then grinding stones and a 4% polishing solution were added, the rectifier was turned on, and the current in the electrolytic cell was adjusted to 0.7 A / dm³. 2 The voltage is 17V. After polishing for 4 hours, the copper-chromium shielding cylinder is removed and cleaned 4 times with water. It is then air-dried in a dry environment.

[0108] Example 31: Unlike Example 28, finishing treatments were performed after the second and third stages. The finishing treatment method was as follows: the copper-chromium shielding cylinder was placed in the electrolytic cell, then grinding stones and a 5% polishing solution were added, the rectifier was turned on, and the current in the electrolytic cell was adjusted to 1A / dm. 2 The voltage is 20V. After polishing for 3 hours, remove the tube and clean the copper-chromium shielding tube 5 times with clean water. Let it air dry naturally in a dry environment.

[0109] Experimental Example: For the copper-chromium shielding cylinders prepared in each embodiment and Comparative Examples 1-6, five samples from each embodiment were taken to test the corrosion resistance, conductivity, and material utilization of the copper-chromium shielding cylinders. The average value of the test results of the five samples in each embodiment was taken as the test result of that embodiment. The specific investigation is as follows:

[0110] Taking CuCr10 material, ingot size φ160mm×4.5mm, blank size φ150mm×4.5mm, and finished product size φ76.8mm (outer diameter)×69.8mm (inner diameter)×85mm (length) as an example;

[0111] 1. Investigating the effect of pretreatment on the performance of copper-chromium shielding cylinders

[0112] Table 1 Performance parameters of copper-chromium shielding cylinders prepared in Examples 1, 8-9 and Comparative Examples 1-2

[0113]

[0114]

[0115] Comparative Example 1: Unlike Example 1, the copper-chromium shielding cylinder is processed by hot extrusion instead of automatic spinning.

[0116] Comparative Example 2: Unlike Example 1, no pretreatment is performed on the copper-chromium contact bar material to be cut.

[0117] Conclusion: As shown in Table 1, compared with Comparative Example 1, the material utilization rate of copper-chromium shielding cylinders processed by automatic spinning is about 19% higher than that of hot extrusion. This is because automatic spinning can continuously form and make full use of raw materials, thereby improving the material utilization rate. The data comparison of Examples 1, Examples 8-9 and Comparative Example 2 shows that the pretreatment of copper-chromium contact bar material to be cut with nitric acid solution can promote the mixing of copper-chromium contact bar material to be cut with the treatment solution, further improve the adhesion of copper-chromium contacts and UV shadowless adhesive, effectively improve the cutting efficiency, and thus improve the performance and corrosion resistance of copper-chromium shielding cylinders.

[0118] 2. Investigate the effects of treatment solution composition and treatment method on the performance of copper-chromium shielding cylinders.

[0119] Table 2 Performance parameters of copper-chromium shielding cylinders prepared in Examples 1, 10-15 and Comparative Examples 3-4

[0120]

[0121]

[0122] Comparative Example 3: Unlike Example 1, 18% methanol, 13% epoxy resin and the remainder deionized water were weighed by mass percentage and mixed evenly to prepare the treatment solution.

[0123] Comparative Example 4: Unlike Example 1, the surface of the copper-chromium contact bar to be cut was directly subjected to microwave irradiation treatment without being allowed to stand during the spraying process.

[0124] Conclusion: Table 2 shows that, comparing the data from Examples 1, 10-11, 14-15, and Comparative Example 3, the material utilization rate of the copper-chromium shielded contact prepared in Comparative Example 3 decreased due to the absence of benzene rings in the treatment solution. This is because the addition of benzene rings improves the lubrication during the copper-chromium contact wire cutting process, increases the adhesion between the contact wire and the contact surface, reduces vibration and movement, improves cutting stability, and further enhances the performance of the copper-chromium shielding cylinder. In contrast, the treatment solutions in Comparative Example 3, Examples 1, 10-11, and 14-15 all contain resin, thus the prepared... The corrosion resistance of the copper-chromium shielding cylinders showed little difference. A comparison of the data from Examples 1, 12-13, and Comparative Example 4 revealed that the lack of a static setting before microwave treatment resulted in a decrease in both the conductivity and corrosion resistance of the copper-chromium shielding cylinders. The main reason for this was that direct microwave treatment after spraying caused overheating of the copper-chromium contact surface to be cut, affecting the adhesion and uniformity of the coating. Microwave treatment after static setting could make the coating more uniform and dense, improve adhesion, improve the surface treatment effect, and further enhance the performance of the copper-chromium shielding cylinder. At the same time, direct microwave treatment after spraying caused the formation of tiny defects and cracks on the material surface, thereby affecting the corrosion resistance of the shielding cylinder.

[0125] 3. Investigate the influence of process parameters during the cutting process on the performance of the copper-chromium shielding cylinder.

[0126] Table 3 Performance parameters of copper-chromium shielding cylinders prepared in Examples 1, 22-23 and Comparative Examples 5-6

[0127] Group Material utilization rate Corrosion rate (mm / a) Conductivity (%IACS) Example 1 93.8％ 0.013 96.13 Example 22 93.2％ 0.021 95.73 Example 23 93.5％ 0.018 96.02 Compare with Example 5 92.8％ 0.029 92.3 Compare with Example 6 92.3％ 0.025 92.01

[0128] Comparative Example 5: Unlike Example 1, in step S3-2, the process parameters set during the cutting process are: wire tension of 45N, wire speed of 700m / min, wire amount of 200m / cycle, and table lifting speed of 4.6mm / min.

[0129] Comparative Example 6: Unlike Example 1, in step S3-2, the process parameters set during the cutting process are as follows: wire tension is 45N, diamond wire winding speed is 1000m / min, diamond wire winding amount is 200m / cycle, and table rising speed is 4.6mm / min.

[0130] Conclusion: Based on the data from Examples 1, 22-23 and Comparative Examples 5-6 in Table 4, it can be seen that the diamond take-up and undo rate in Comparative Example 5 is lower than the range specified in this application, resulting in an uneven cutting surface. In contrast, the take-up and undo rate in Comparative Example 6 is higher than the range specified in this application, leading to uneven cutting and thus reducing the material utilization rate and performance of the copper-chromium shielding cylinder. Therefore, Example 1 is selected as the optimal solution.

[0131] 4. Investigate the influence of process parameters during the cutting process on the performance of the copper-chromium shielding cylinder.

[0132] Table 4 Performance parameters of the copper-chromium shielding cylinders prepared in Examples 1 and 24-31

[0133]

[0134]

[0135] Conclusion: Based on the data from Examples 1 and 24-28 in Table 4, adjusting the feed rate of the rotary cutter according to the spindle speed can better control the material forming while promoting faster material flow and redistribution. Simultaneously, it can effectively improve the performance of the shielding cylinder without causing excessive compression or stretching of the material. Therefore, Example 27 is the optimal solution. Furthermore, comparing the data from Examples 27 and 29-31, it can be seen that performing a finishing process after the second and third stage adjustments can further improve the corrosion resistance and conductivity of the copper-chromium shielding cylinder. Therefore, Example 30 is the optimal solution.

Claims

1. A method for processing a copper-chromium shielding cylinder for a vacuum interrupter, characterized in that, Includes the following steps: S1, copper-chromium forging ingot CuCr1-CrCr30 materials with a Brinell hardness of 50-120HB, prepared by vacuum melting, were used as raw materials for forging to obtain copper-chromium forging ingots of the target size. S2, Rough turning of outer diameter, sawing of material head The surface of the copper-chromium forging ingot is rough-turned to 1-4 mm, and then 2-6 cm is removed from the top and bottom ends of the forging ingot using a saw to obtain the copper-chromium contact bar material to be cut. S3, Multi-wire EDM machining of blanks S3-1, Rod Curing The number of copper-chromium contact rods to be cut is adjusted according to the diameter of the rods, and they are fixed to a transparent glass plate with UV-curing adhesive. Then, a UV curing lamp is used for curing, with a curing time of 1-15 minutes. The UV-curing adhesive has a tensile strength of 13-15 MPa, a shear strength of 16-18 MPa, and a coating width of 5-20 mm. The transparent glass plate has a light transmittance >93%. S3-2, Cutting and Processing Set the cutting thickness standard value and tolerance according to the program, fix the transparent glass plate to the worktable of the diamond wire multi-wire cutting machine, raise the worktable so that the starting cutting surface of the copper-chromium contact bar to be cut is close to the diamond wire, start the cutting program to cut, and spray coolant on the surface of the copper-chromium contact bar to be cut at a rate of 3-5mL / s. When the diamond wire cuts 2-6mm to the surface of the transparent glass plate, stop the machine to complete the cutting and obtain a copper-chromium flat blank. S4, Automatic Spinning Prepare spinning die 76.8mm×85mm and top mold The copper-chromium flat plate blank prepared in step S3-2 is 70mm × 80mm. Then, it is vacuum heated to 400-900℃ and held for 5-90 minutes until the vacuum degree reaches 1×10⁻⁶. -2 Pa, after the copper-chromium flat blank is taken out and fixed on the mold of the spinning machine, the machine tool is driven with the spindle speed of 50-1500 r / min and the tail force ≤10kN, so that the copper-chromium flat blank rotates with the machine spindle. At this time, the spinning cutter applies pressure to the copper-chromium flat blank with a feed rate of 5-50 mil / cutter, so that it produces plastic deformation. The spinning time is 3-8min, so that the local plastic deformation of the copper-chromium flat blank extends to the entire surface and adheres tightly to the mold, thus producing the copper-chromium shielding cylinder part; S5, Finished Products After the copper-chromium shielding cylinder parts are polished, they are processed into finished products using automated processes to obtain copper-chromium shielding cylinders for vacuum interrupters. Before step S3-1, the copper-chromium contact bar material to be cut undergoes surface treatment; the surface treatment method is as follows: Weigh out 15-20% methanol, 10-15% epoxy resin, 5-7% benzene rings, and the balance deionized water by mass percentage, and mix them evenly to prepare a treatment solution. Prepare the treatment solution according to the weight-to-volume ratio of the copper-chromium contact bar to be cut to the treatment solution of 1.3-1.5 kg: 300-330 mL, and divide it into 2-4 equal portions. Take one portion of the treatment solution and spray it onto the dried surface of the copper-chromium contact bar to be cut at a rate of 5-8 mL / s. After spraying, let it stand for 30-50 seconds. ,Then Using an irradiation intensity of 10-12 W / cm 2 The surface of the copper-chromium contact bar is irradiated with microwave for 2-4 minutes. After the initial treatment, another portion of the treatment solution is taken and sprayed onto the surface of the copper-chromium contact bar to be cut. The settling time after spraying is increased by 10-15 seconds each time, and then the irradiation intensity is adjusted and the treatment continues for 1-2 minutes. This cycle is repeated until the treatment solution is completely sprayed. The spraying rate of the treatment solution is increased by 1-1.5 mL / s each time, and the irradiation intensity is increased by 8-10 W / cm² each time. 2 Improve; In step S4, the feed rate of the rotary cutter is adjusted according to the spindle speed and is divided into four stages: The first stage: the initial spindle speed is 50 r / min, and then it is increased to 300-320 r / min at a rate of 160 r / min. During this process, the feed rate of the rotary cutter is 45-50 microns / cutter. Second stage: When the spindle speed reaches 300-320 r / min, the spindle speed is increased to 800-820 r / min at a rate of 280 r / min. During this process, the rotary cutter is reduced from 45-50 mils / cut to 25-30 mils / cut at a rate of 8-10 mils / cut per minute and then maintained. The third stage: When the spindle speed reaches 800-820 r / min, the spindle speed is increased to 1480-1500 r / min at a rate of 350 r / min. During this process, the rotary cutter is reduced from 25-30 mils / cut to 15-20 mils / cut at a rate of 5-7 mils / cut per minute and then maintained. Fourth stage: When the spindle speed reaches 1480-1500 r / min, the spindle speed is reduced to 50 r / min at a rate of 420 r / min. During this period, the feed rate of the rotary cutter is maintained at 5-10 microns / cutter until the spinning process is completed.

2. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, In step S2, during the rough turning of the outer diameter, the depth of cut is 1-3 mm, the spindle speed is 500-800 r / min, and the feed rate is 0.1-0.4 mm / r.

3. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, The mixing method involves mixing methanol, epoxy resin, and deionized water at a speed of 400-450 r / min for 20-30 minutes, then dividing the benzene ring into 4-6 equal parts and spraying it every 2-4 minutes during the mixing process until the mixing is complete.

4. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, The copper-chromium contact bar material to be cut is pretreated by immersing it in a 3-4% nitric acid solution for 15-25 minutes, rinsing it with deionized water 1-3 times, and finally drying it in a drying oven at 50-55℃ for 25-35 minutes for later use.

5. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, In step S3-1, the dimensions of the transparent glass plate are 450mm×200mm×10-30mm. The relationship between the number of copper-chromium contact bars to be cut and their diameter is as follows: if the diameter D of the copper-chromium contact bars to be cut is ≤40mm, then the number of bars is 2-5; if the diameter D of the copper-chromium contact bars to be cut is >60mm, then the number of bars is 1-2.

6. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, In step S3-2, the process parameters set during the cutting process are as follows: wire tension is 10-80N, diamond wire winding speed is 500-900m / min, diamond wire winding amount is 300-600m / cycle, and table rising speed is 1.2-8.0mm / min.

7. The processing method of a copper-chromium shielding cylinder for a vacuum interrupter as described in claim 1, characterized in that, In step S3-2, the diamond wire is a diamond wire with a specification D=0.10-0.60mm; the coolant is a water-soluble cutting fluid with a preparation ratio of 1-10wt%.

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