A surface treatment method suitable for high-voltage large-size copper-chromium contact materials

Abstract

The application discloses a surface treatment method suitable for high-voltage large-size copper-chromium contact materials, and the surface treatment method comprises the following steps: blank mechanical machining and oil removal treatment, wet sand blasting on an arc surface, magnetic grinding, vacuum cleaning and drying, and product packaging and warehousing. The surface treatment method has the advantages of simple and controllable process, good product surface consistency, effective tool cost saving, high machining efficiency, and the significance of batch production and machining popularization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloy contact, in particular to a surface treatment method suitable for high-voltage large-specification copper-chromium contact material. BACKGROUND

[0002] The copper-chromium contact material has excellent breaking capacity and voltage resistance, and good arc ablation resistance and anti-welding performance, and has been widely used in vacuum circuit breakers. With the continuous development of vacuum switches towards high voltage, large capacity and miniaturization, it is required to further improve the voltage resistance of the copper-chromium contact material and reduce the contact surface resistance, which puts higher technical requirements on the contact material and processing method.

[0003] An ideal contact material should have the following properties: ① large current breaking capacity ② high withstand voltage capacity ③ small contact resistance ④ good anti-welding performance ⑤ low contact wear ⑥ small breaking current ⑦ sufficient mechanical strength ⑧ good processing performance. Advanced surface treatment technology is the basis and indispensable effective technical means for the development of copper-chromium contact to high-voltage industry manufacturing, which can improve the performance of contact components without changing the structure and material of the contact components, ensure service safety and prolong service life.

[0004] At present, high chromium content (Cr content ≥ 40%) and large specification (diameter Φ ≥ 100 mm) copper-chromium contact materials are generally used in high voltage. During the machining process, the surface roughness of the contact component has always been an important factor for vacuum circuit breaker manufacturers to consider in designing and processing schemes and stable operation of equipment. Generally, hard alloy cutters are used during the machining process of copper-chromium contacts, and the surface roughness of the CuCr contact material processed by the cutter decreases with the increase of Cr content, especially the high Cr content CuCr contact material is difficult to obtain excellent surface roughness through single machining, and it is impossible to meet the technical requirements of the specific contact arc surface roughness Ra0.3 and below. Especially when the Cr content of the copper-chromium contact reaches 40% or more, due to the presence of high-hardness metal chromium phase, it is difficult to achieve good surface quality during processing, the cutter is severely worn, the processing efficiency is low, the surface quality is difficult to guarantee, resulting in a very low first-time yield of high-chromium products, and even causing product scrap, high processing cost and low efficiency.

[0005] It is generally believed in the industry that the smaller the arc surface roughness, the better, which is beneficial to reducing the contact surface resistance and facilitating contact breaking; the welding surface roughness is controlled within a certain range (generally Ra ≤ 3.2 μm), which is beneficial to ensuring the wettability of the solder during vacuum brazing of the contact and improving the strength of the vacuum brazing. This is of great significance to improve the stability of the vacuum copper-chromium contact during breaking, reduce the failure rate of the vacuum circuit breaker, and maintain the safe and stable operation of the power grid. SUMMARY

[0006] To solve the above technical problems, the application provides a surface treatment method suitable for high-voltage large-specification copper-chromium contact materials.

[0007] The technical scheme of the application is as follows: a surface treatment method suitable for high-voltage large-specification copper-chromium contact materials, comprising the following steps:

[0008] S1, blank mechanical processing and oil removal treatment:

[0009] According to the technical requirements of the process drawing, full-size mechanical processing is performed on the blank of the required specification to obtain a copper-chromium contact with a roughness of Ra3.1-3.3 μm, and then an oil removal agent is used to perform oil removal treatment on the copper-chromium contact;

[0010] S2, wet sanding of the arcing surface:

[0011] The arcing surface and the slotted intersecting edge of the copper-chromium contact obtained in S1 are subjected to wet sanding treatment for 1-3 min by using a plane grinding and brushing machine group with uniform process parameters, and when the thickness of the copper-chromium contact is <5 mm, the wet sanding speed is 1500-3000 r / min, and when the thickness of the copper-chromium contact is ≥5 mm, the wet sanding speed is 500-1500 r / min; the amount of the copper-chromium contact subjected to single wet sanding treatment is 4-16 pieces, and a contact with an arcing surface roughness of Ra0.2-0.3 μm and a welding surface roughness of Ra3.1-3.3 μm is obtained;

[0012] S3, magnetic grinding:

[0013] The contact obtained in S2 is laid flat in a square stainless steel cleaning frame without overlapping after being coated with an automatic magnetic grinding medium, and is subjected to automatic magnetic grinding treatment, a plurality of specifications of SUS304 magnetized combined steel needles combined in proportion are selected as the abrasive, and a contact with a further reduced arcing surface roughness is obtained after completion;

[0014] S4, vacuum cleaning and drying:

[0015] A vacuum environment-friendly carbon hydrogen cleaning machine is used to perform vacuum cleaning and drying on the contact obtained in S3, and the environment-friendly carbon hydrogen cleaning agent used for vacuum cleaning is distilled and recycled for reuse, and a contact with a cleanliness of <5 RFU is obtained after vacuum cleaning and drying;

[0016] S5, finished product packaging and storage:

[0017] The contact obtained in S4 is vacuum packaged, and corresponding blister packaging is selected according to the size of the contact, there is a gap between the contacts, and a silica gel desiccant is placed in the blister packaging.

[0018] Further, in the S1, the blank with the required specification is a blank with Cr content ≥ 40wt.%, and diameter specification Φ ≥ 100mm.

[0019] Description: The blank with the above specification can be used to make copper-chromium contact suitable for high voltage.

[0020] Further, in the S2, the material of the plane brush used for sanding is one of silicon carbide or brown corundum, the particle size of the plane brush is selected from 120-320 mesh, the height of the new brush is 54-56mm, and the height of the waste brush is 29-31mm.

[0021] Description: The sanding efficiency of the plane brush abrasive per unit time is high, and the sanding plane brush abrasive generated has little residue on the product surface, which is easy to clean and does not affect the subsequent vacuum brazing and electrical performance of the contact.

[0022] Further, in the S2, the wet sanding includes the following parameters: plane brush compensation period 80-300 pieces, plane brush compensation amount 0.1-0.5mm, plane brush feeding depth 1.0-3.0mm; plane brush rotation speed 500-3000r / min, revolution speed 10-50r / min, feeding processing area conveyor belt speed 0.5-3m / min.

[0023] Description: Within this range, the appearance color of the treated contact is consistent, and some burrs can also be removed; too large compensation period of the brush will cause excessive brushing, resulting in abnormal appearance color of the product and size out-of-tolerance deformation; too small compensation period cannot achieve the brushing effect, the appearance color of the product is inconsistent, and the edge burr cannot be effectively removed; too large or too small compensation amount of the brush and the following process parameter range will cause the same problems; the above process parameters are comprehensive influencing factors, which together ensure that the contact achieves the expected effect after treatment.

[0024] Further, in the S3, the stainless steel cleaning frame has a specification of 480mm×320mm×110mm and a material of SUS304; the SUS304 magnetized combined steel needle is composed of four types of steel needles with diameters of Ф1.0mm, Ф0.8mm, Ф0.5mm and Ф0.3mm in a weight ratio of 1:2:2:1, and the length of the steel needles is 8mm.

[0025] Description: The above combined steel needle is selected as the abrasive, and the specifications of the combined steel needle are large and small, which can be used for grinding and polishing treatment of multiple positions such as contact groove, hole and step, effectively removing surface dirt and virtual hanging small burrs, and ensuring the appearance quality of the contact.

[0026] Further, in the S3, the parameters of the automatic magnetic grinding include: grinding frequency 25-60Hz, translation frequency of the magnetic field 5-20Hz, and grinding time 5-30min.

[0027] Note: The above selected parameters can ensure that the contact is fully ground and the small burrs are removed to meet the technical standards; if the grinding frequency and the translation frequency of the magnetic field are too high, the contact will be damaged during grinding; if they are too low, the contact will not be fully ground, the surface of the contact will not be polished, and the small burrs on the surface of the contact cannot be effectively removed.

[0028] Further, in the S4, the cleaning and drying include: steam degreasing for 30-120s, ultrasonic cleaning for 10-60s, spraying for 30-90s, steam degreasing for 30-60s, vacuum drying for 120-480s, and vacuum drying temperature of 80-100℃.

[0029] Note: In the above conditions, the vacuum negative pressure environment can ensure that the contact is not oxidized during cleaning and drying, and there is no impurity residue on the surface of the contact after cleaning.

[0030] Further, in the S2, the medium of the wet sanding and the medium of the automatic magnetic grinding in the S3 are both extreme pressure precision cutting oil.

[0031] Note: The medium of the wet sanding is selected as the extreme pressure precision cutting oil to ensure that the product is not oxidized during processing; the same medium oil is selected for the automatic magnetic grinding and the wet sanding of the arcing surface, so that the intermediate transfer process does not need to be cleaned, and the next process can be directly entered, thereby improving the processing efficiency.

[0032] Further, in the S1, the oil removing agent is KM0121 oil removing agent.

[0033] Note: The oil removing agent is environmentally friendly and non-toxic, does not contain heavy metals and nitrogen, phosphorus, fluorine, etc., meets the RoHS requirements, has fast oil removing speed, strong oil stain dissolving capacity, is beneficial to improving production efficiency, has weak alkalinity, does not corrode metal during cleaning, and does not change the size and original color of the workpiece.

[0034] Further, the method for oil removing treatment is:

[0035] S1-1: After the copper-chromium contact is soaked in the oil removing agent for 2-3min, the temperature is raised to 70-80℃, 0.6%-0.8% boric acid solution by mass percentage of the oil removing agent is added to adjust the pH to 6-8 every 5-10℃ of temperature rise, the molar concentration of the boric acid solution is 0.1-0.3mol / L, and the temperature rise is ended;

[0036] S1-2: After the required temperature is reached, the temperature is maintained, and when the pH of the oil removing agent with the added boric acid solution starts to decrease from 10.5, the temperature maintenance time is gradually extended at a rate of 1-3min / pH from the initial 5-10min;

[0037] The oil removing agent comprises, by mass percentage: polyethylene glycol octylphenyl ether 4-5 %, phosphate ester salt 3-5 %, anhydrous sodium silicate 2-4 %, sodium pyrophosphate 2-4 %, dipropylene glycol methyl ether 4-6 %, sodium o-phenylphenol 0.5-1.5 %, and the balance of water.

[0038] The copper-chromium contact is soaked in the oil removing agent to remove oil from the copper-chromium contact; the oil removing agent containing sodium o-phenylphenol can enhance the oil removing effect and improve the anti-rust performance of the copper-chromium contact; and the borate solution is added to adjust the pH during temperature rising to neutralize the surface of the copper-chromium contact, reduce the oxidation degree of the copper-chromium contact in subsequent processing, and limit the relationship between the holding time and the pH, thereby further enhancing the consistency of the surface treatment of the copper-chromium contact.

[0039] The present application has the following advantages:

[0040] (1) The present application uses wet sanding to treat the arc-burning surface of a large-size contact, and the roughness of the arc-burning surface of the obtained contact can reach the Ra0.2-0.3 μm level, and the roughness of the welding surface without sanding treatment is Ra3.2 μm, which effectively reduces the contact surface resistance, ensures smooth transition of the arc-burning surface of the contact, effectively avoids the performance failure of the vacuum arc chamber caused by the tip discharge during voltage and current aging process, and is beneficial to ensuring the wettability of the solder during vacuum brazing of the contact, improving the strength of the vacuum brazing, and improving the surface quality of the product.

[0041] (2) The present application uses magnetic grinding process to treat the surface of the contact, and the abrasive is SUS304 magnetized combined steel needle, which can grind and polish the positions such as the groove, hole and step of the contact, remove surface dirt and virtual hanging micro burrs, and ensure the appearance quality of the contact.

[0042] (3) The present application soaks the contact in oil removing agent and adjusts the pH to remove oil from the contact, which further enhances the anti-rust effect of the contact, reduces the oxidation degree of the contact in surface treatment, and improves the surface consistency of the contact. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is the metallographic phase diagram of the arc-burning surface of the contact of the present application under 50x magnification;

[0044] Figure 2 is the metallographic phase diagram of the arc-burning surface of the contact of the present application under 100x magnification;

[0045] Figure 3 is the metallographic phase diagram of the welding surface of the contact of the present application under 50x magnification;

[0046] Figure 4 is the metallographic phase diagram of the welding surface of the contact of the present application under 100x magnification;

[0047] Figure 5 is the microstructure of the contact of the present application after vacuum brazing under 50x magnification;

[0048] Figure 6 is the microstructure of the contact of the present application after vacuum brazing under 100x magnification;

[0049] Figure 7 is a schematic diagram of the stainless steel cleaning frame used in the method of the present application;

[0050] Figure 8 is a schematic diagram of the blister box packaging used in the method of the present application. DETAILED DESCRIPTION

[0051] The present application will be described in further detail below in conjunction with specific embodiments in order to better illustrate the advantages of the present application.

[0052] Example 1

[0053] S1, blank machining and oil removal treatment:

[0054] A blank with a Cr content of 42wt.% and a diameter of Φ105mm was subjected to full-size machining according to the technical requirements of the process drawing, to obtain a copper-chromium contact with a roughness of Ra3.2μm, and then subjected to oil removal treatment using KM0121 oil removal agent;

[0055] S2, wet sanding of the arcing surface:

[0056] The arcing surface and the slotted intersecting edge of the copper-chromium contact obtained in S1 were subjected to wet sanding treatment for 2min using a plane grinding brush machine with uniform process parameters, the thickness of the copper-chromium contact was 4mm, the wet sanding speed was 2250r / min, the wet sanding medium was a commercially available extreme pressure precision cutting oil, the material of the plane brush used for wet sanding was silicon carbide, the particle size of the plane brush was selected to be 200 mesh, the height of the new brush was 55mm, and the height of the waste brush was 30mm;

[0057] The plane brush compensation period was 180 pieces, the plane brush compensation amount was 0.3mm, the plane brush feed depth was 2.0mm, the plane brush rotation speed was 1700r / min, the revolution speed was 30r / min, the feed processing area conveying belt speed was 2m / min, and the amount of copper-chromium contact subjected to single wet sanding treatment was 9 pieces, to obtain a contact with an arcing surface roughness of Ra0.25μm and a welding surface roughness of Ra3.2μm;

[0058] S3, magnetic grinding:

[0059] The contact obtained in S2 is laid flat without overlapping in a square stainless steel cleaning frame with a size of 480mm*320mm*110mm and a material of SUS304 after being coated with a medium for automatic magnetic force grinding; the SUS304 magnetized combined steel needle is composed of four kinds of steel needles with a size of Ф1.0mm, Ф0.8mm, Ф0.5mm and Ф0.3mm according to a weight ratio of 1:2:2:1, and the length of the steel needle is 8mm; automatic magnetic force grinding is performed, the oil used for the grinding medium is the same as the sand polishing medium, and a contact with a further reduced roughness of the arcing surface is obtained after completion;

[0060] S4, vacuum cleaning and drying:

[0061] The contact obtained in S3 is subjected to vacuum cleaning and drying by using a vacuum environment-friendly carbon hydrogen cleaning machine, steam degreasing for 75s, ultrasonic cleaning for 35s, spraying for 60s, steam degreasing for 45s, and vacuum drying for 300s at a vacuum drying temperature of 90℃; the DN-200 environment-friendly carbon hydrogen cleaning agent used for vacuum cleaning is subjected to distillation and recycling for reuse, and the contact with a cleanliness of 4RFU is obtained after vacuum cleaning and drying;

[0062] S5, product packaging and storage:

[0063] The contact obtained in S4 is subjected to vacuum packaging, and the corresponding blister box packaging is selected according to the size of the contact; there is a gap between the contacts, and silica gel desiccant is placed in the blister box packaging.

[0064] Example 2

[0065] The difference between this embodiment and Example 1 is that the granularity of the flat brush is selected to be 120 meshes, the height of the new brush is 54mm, the height of the waste brush is 29mm; the flat brush compensation period is 80 pieces, the flat brush compensation amount is 0.1mm, and the flat brush feeding depth is 1.0mm.

[0066] Example 3

[0067] The difference between this embodiment and Example 1 is that the granularity of the flat brush is selected to be 320 meshes, the height of the new brush is 56mm, the height of the waste brush is 31mm; the flat brush compensation period is 300 pieces, the flat brush compensation amount is 0.5mm, and the flat brush feeding depth is 3.0mm.

[0068] Example 4

[0069] The difference between this embodiment and Example 1 is that the rotation speed of the flat brush is 500r / min, the revolution speed is 10r / min, and the feeding processing zone conveying belt speed is 0.5m / min.

[0070] Example 5

[0071] The difference between this embodiment and embodiment 1 is that the flat brush rotation speed is 3000 r / min, the revolution speed is 50 r / min, and the feeding processing zone conveying belt speed is 3 m / min.

[0072] Embodiment 6

[0073] The difference between this embodiment and embodiment 1 is that the wet sanding speed is 1500 r / min, the amount of copper-chromium contacts treated by single wet sanding is 4 pieces; the polishing frequency is 25 Hz, and the translation frequency of the magnetic field is 5 Hz.

[0074] Embodiment 7

[0075] The difference between this embodiment and embodiment 1 is that the wet sanding speed is 3000 r / min, the amount of copper-chromium contacts treated by single wet sanding is 16 pieces; the polishing frequency is 60 Hz, and the translation frequency of the magnetic field is 20 Hz.

[0076] Embodiment 8

[0077] The difference between this embodiment and embodiment 1 is that the wet sanding treatment is 1 min, and the polishing time is 5 min.

[0078] Embodiment 9

[0079] The difference between this embodiment and embodiment 1 is that the wet sanding treatment is 3 min, and the polishing time is 30 min.

[0080] Embodiment 10

[0081] The difference between this embodiment and embodiment 1 is that the steam degreasing is 30 s, the ultrasonic cleaning is 10 s, the spraying is 30 s, the steam degreasing is 30 s, the vacuum drying is 120 s, and the vacuum drying temperature is 80℃.

[0082] Embodiment 11

[0083] The difference between this embodiment and embodiment 1 is that the steam degreasing is 120 s, the ultrasonic cleaning is 60 s, the spraying is 90 s, the steam degreasing is 60 s, the vacuum drying is 480 s, and the vacuum drying temperature is 100℃.

[0084] Embodiment 12

[0085] The difference between this embodiment and embodiment 1 is that the method for oil removal treatment is:

[0086] S1-1: The copper-chromium contact is soaked in the oil removal agent for 2.5 min, then the temperature is raised to 75℃, and for every 8℃ of temperature rise, a 0.7% boric acid solution by mass percentage is added to adjust the pH to 7, the molar concentration of the boric acid solution is 0.2 mol / L, until the end of temperature rise;

[0087] S1-2: After reaching the required temperature, the temperature is kept constant, and when the pH of the degreasing agent to which the boric acid solution is added decreases by 1 from 10.5, the holding time is gradually extended at a rate of 2 min / pH from the initial 8 min;

[0088] The degreasing agent comprises, by mass percentage, polyethylene glycol octylphenyl ether 4.5%, phosphate ester salt 4%, anhydrous sodium silicate 3%, sodium pyrophosphate 3%, dipropylene glycol methyl ether 5%, sodium o-phenylphenol 1%, and the balance of water.

[0089] Example 13

[0090] The difference between this example and Example 12 is that in step S1-1, after the copper-chromium contact is soaked in the degreasing agent for 2 min, the temperature is raised to 70°C.

[0091] Example 14

[0092] The difference between this example and Example 12 is that in step S1-1, after the copper-chromium contact is soaked in the degreasing agent for 3 min, the temperature is raised to 80°C.

[0093] Example 15

[0094] The difference between this example and Example 12 is that in step S1-1, every time the temperature is raised by 5°C, a boric acid solution with a mass percentage of 0.6% in the degreasing agent is added to adjust the pH to 6, and the molar concentration of the boric acid solution is 0.1 mol / L.

[0095] Example 16

[0096] The difference between this example and Example 12 is that in step S1-1, every time the temperature is raised by 10°C, a boric acid solution with a mass percentage of 0.8% in the degreasing agent is added to adjust the pH to 8, and the molar concentration of the boric acid solution is 0.3 mol / L.

[0097] Example 17

[0098] The difference between this example and Example 12 is that in step S1-2, the holding time is gradually extended at a rate of 1 min / pH from the initial 5 min.

[0099] Example 18

[0100] The difference between this example and Example 12 is that in step S1-2, the holding time is gradually extended at a rate of 3 min / pH from the initial 10 min.

[0101] Example 19

[0102] The oil removing agent of the embodiment differs from that of embodiment 12 in that it comprises, by mass percentage, polyethylene glycol octylphenyl ether 4%, phosphate ester salt 3%, anhydrous sodium silicate 2%, sodium pyrophosphate 2%, dipropylene glycol methyl ether 4%, sodium o-phenylphenol 0.5%, and the balance of water.

[0103] Embodiment 20

[0104] The oil removing agent of the embodiment differs from that of embodiment 12 in that it comprises, by mass percentage, polyethylene glycol octylphenyl ether 5%, phosphate ester salt 5%, anhydrous sodium silicate 4%, sodium pyrophosphate 4%, dipropylene glycol methyl ether 6%, sodium o-phenylphenol 1.5%, and the balance of water.

[0105] Experimental example

[0106] The metallographic examination of the arcing surface and the welding surface of the copper-chromium contact prepared in embodiment 1 obtains the metallographic images shown in FIGS. 1 and 2, which are 50x and 100x, respectively, and according to the observation, it can be seen that the copper-chromium contact prepared by the method has a small roughness and a uniform structure. Figures 1-4 Figures 1-4 The metallographic examination of the arcing surface and the welding surface of the copper-chromium contact prepared in embodiment 1 obtains the metallographic images shown in FIGS. 1 and 2, which are 50x and 100x, respectively, and according to the observation, it can be seen that the copper-chromium contact prepared by the method has a small roughness and a uniform structure.

[0107] The vacuum brazing of the copper-chromium contact prepared in embodiment 1 obtains the scanning images shown in FIGS. 3 and 4, which are 50x and 100x, respectively, and according to the observation, it can be seen that the welding seam is uniformly filled and has no defects such as pores, slag, incomplete penetration, incomplete fusion and cracks, and has a relatively good performance. Figure 5 6 The vacuum brazing of the copper-chromium contact prepared in embodiment 1 obtains the scanning images shown in FIGS. 3 and 4, which are 50x and 100x, respectively, and according to the observation, it can be seen that the welding seam is uniformly filled and has no defects such as pores, slag, incomplete penetration, incomplete fusion and cracks, and has a relatively good performance. Figure 5 6 The vacuum brazing of the copper-chromium contact prepared in embodiment 1 obtains the scanning images shown in FIGS. 3 and 4, which are 50x and 100x, respectively, and according to the observation, it can be seen that the welding seam is uniformly filled and has no defects such as pores, slag, incomplete penetration, incomplete fusion and cracks, and has a relatively good performance.

[0108] For the copper-chromium contacts prepared in each embodiment, 5 sample pieces of each embodiment are taken to test the performance of the copper-chromium contact, and the performance measurement results of the 5 sample pieces of each embodiment are averaged to be the performance measurement result of the embodiment, and the specific exploration is as follows:

[0109] 1. Explore the influence of embodiments 1-9 on the roughness of the arcing surface of the prepared copper-chromium contact.

[0110] With embodiments 1-9 as the comparison, the results are shown in Table 1.

[0111] Table 1: Arcing surface roughness test table of each sample of embodiments 1-9

[0112] Group Roughness / Ra Example 1 0.202 Example 2 0.227 Example 3 0.233 Example 4 0.289 Example 5 0.276 Example 6 0.244 Example 7 0.241 Example 8 0.219 Example 9 0.194

[0113] ​​​From the results of Table 1, it can be seen that the parameters involved in Examples 1-9 have certain influence on the roughness of the prepared copper-chromium contact arc surface, and through comparison, it can be seen that the parameters such as the speed of the plane brush need to be adjusted according to the thickness of the product, and under the condition that the thickness of the product is certain, too fast speed will lead to excessive brushing, and too slow speed will not achieve the effect, affecting the improvement efficiency of the roughness; although the roughness of Example 9 is lower, the wet sanding time required by Example 9 is longer, and the grinding is longer, but compared with the roughness of Example 1, the decrease is smaller, so from the economic point of view, the roughness of the copper-chromium contact arc surface prepared by the parameter design of Example 1 is relatively more optimal.

[0114] 2, explore the influence of Examples 1, 10-11 on the surface cleanliness of the prepared copper-chromium contact.

[0115] Examples 1, 10-11 are used as a comparison, and the results are shown in Table 2:

[0116] Table 2 surface cleanliness test table of each sample of Examples 1, 10-11

[0117] Group Surface Cleanliness / RFU Example 1 1.6 Example 10 2.1 Example 11 1.4

[0118] From the results of Table 2, it can be seen that the parameters involved in Examples 1, 10-11 have certain influence on the surface cleanliness of the prepared copper-chromium contact, and through comparison, it can be seen that although the surface cleanliness of Example 11 is higher than that of Example 1 and Example 10, the time required by Example 11 is longer, and the drying temperature is higher, so from the economic point of view, the surface cleanliness of the copper-chromium contact prepared by the parameter design of Example 1 is relatively more optimal.

[0119] 3, explore the influence of Examples 1, 12-20 on the surface cleanliness of the prepared copper-chromium contact.

[0120] Examples 1, 12-20 are used as a comparison, and the results are shown in Table 3:

[0121] Table 3 surface cleanliness test table of each sample of Examples 1, 12-20

[0122]

[0123] Comparative Example 1 differs from Example 12 in that the boric acid solution is added all at once during the heating process;

[0124] Comparative Example 2 differs from Example 12 in that the holding time remains unchanged at the initial 5-10 min;

[0125] Comparative Example 3 differs from Example 12 in that the sodium o-phenylphenol component in the oil removing agent is replaced by amino benzene sulfonamide;

[0126] From the results of Table 3, it can be seen that the parameters involved in Examples 1, 12-20 have certain effects on the surface cleanliness of the prepared copper-chromium contact. By comparing Example 1, it can be seen that the cleanliness degree is lower than that of Example 12 when the boric acid solution is added at one time. By comparing Example 2, it can be seen that the cleanliness degree is also lower than that of Example 12 when the holding time is kept unchanged. By comparing Example 3, it can be seen that the cleanliness degree is improved when the amino benzene sulfonamide in the ordinary oil removal agent is replaced by sodium o-phenylphenol. Therefore, the cleanliness degrees of Examples 1, 2 and 3 are all lower than that of Example 12.

[0127] By comparison, it can be seen that although the surface cleanliness of Examples 14 and 18 is higher than that of Example 12, the time and temperature required by Example 14 are longer and higher, and the holding time required by Example 18 is longer. Therefore, from the economic point of view, the surface cleanliness of the copper-chromium contact prepared by the parameter design of Example 12 is relatively better.

Claims

1. A surface treatment method suitable for high voltage large gauge copper chromium contact material, characterized by, It comprises the following steps: S1, blank mechanical processing and oil removal treatment: According to the technical requirements of the process drawing, the full-size mechanical processing is carried out on the blank of the required specification to obtain the copper-chromium contactor with roughness of Ra3.1-3.3 μm, and then the oil removal agent is used for oil removal treatment on the copper-chromium contactor; S2, wet sanding of the arcing surface: The planar brush unit is used for wet sanding treatment of the arcing surface and the slot intersecting edge of the copper-chromium contactor obtained in S1 for 1-3 min with uniform process parameters, and when the thickness of the copper-chromium contactor is <5 mm, the wet sanding speed is 1500-3000 r / min, and when the thickness of the copper-chromium contactor is ≥5 mm, the wet sanding speed is 500-1500 r / min; the amount of the copper-chromium contactor treated by single wet sanding is 4-16 pieces, and the contactor with roughness of Ra0.2-0.3 μm on the arcing surface and roughness of Ra3.1-3.3 μm on the welding surface is obtained; The material of the planar brush used for sanding is one of silicon carbide or brown corundum, the particle size of the planar brush is selected from 120-320 mesh, the height of the new brush is 54-56 mm, and the height of the waste brush is 29-31 mm; The wet sanding comprises the following parameters: wet sanding for 1-3 min, planar brush compensation period for 80-300 pieces, planar brush compensation amount for 0.1-0.5 mm, planar brush feeding depth for 1.0-3.0 mm, planar brush rotating speed for 500-3000 r / min, revolution speed for 10-50 r / min, and feeding processing area conveying belt speed for 0.5-3 m / min; S3, magnetic grinding: The contactor obtained in S2 is laid in a square stainless steel cleaning frame without overlapping after being coated with the medium for automatic magnetic grinding, and the automatic magnetic grinding treatment is carried out, a plurality of specifications of SUS304 magnetized combined steel needles combined in proportion are selected as the abrasive, and after completion, the contactor with further reduced roughness of the arcing surface is obtained; The specification of the stainless steel cleaning frame is 480 mm×320 mm×110 mm, and the material is SUS304; the SUS304 magnetized combined steel needle is composed of steel needles with four specifications of Ф1.0 mm, Ф0.8 mm, Ф0.5 mm and Ф0.3 mm in a weight ratio of 1:2:2:1, and the length of the steel needles is 8 mm; S4, vacuum cleaning and drying: The contactor obtained in S3 is subjected to vacuum cleaning and drying by using a vacuum environment-friendly carbon hydrogen cleaning machine, the environment-friendly carbon hydrogen cleaning agent used for vacuum cleaning is subjected to distillation and recycling for reuse, and the contactor with cleanliness <5 RFU is obtained after vacuum cleaning and drying; The cleaning and drying comprises: steam degreasing for 30-120 s, ultrasonic cleaning for 10-60 s, spraying for 30-90 s, steam degreasing for 30-60 s, vacuum drying for 120-480 s, and vacuum drying temperature for 80-100℃; S5, finished product packaging and storage: The contactor obtained in S4 is subjected to vacuum packaging, and the corresponding blister box packaging is selected according to the size of the contactor, there is a gap between the contactors, and silica gel desiccant is placed in the blister box packaging.

2. A surface treatment method for high voltage large size copper chromium contact material as claimed in claim 1 wherein, In S1, the blank with the required specification is a blank with Cr content ≥40 wt.% and diameter specification Φ≥100 mm.

3. A surface treatment method for high voltage large size copper chromium contact material as claimed in claim 1 wherein, The parameters of the automatic magnetic lapping in S3 include lapping frequency of 25-60 Hz, translation frequency of magnetic field of 5-20 Hz, and lapping time of 5-30 min.

4. The surface treatment method for high-voltage large-size copper-chromium contact materials according to claim 1, wherein the medium for wet sanding in S2 and the medium for automatic magnetic lapping in S3 are both extreme pressure precision cutting oil.

5. A surface treatment method for high voltage large size copper chromium contact material as claimed in claim 1 wherein, In S1, the oil removing agent is KM0121 oil removing agent.

6. A surface treatment method for high voltage large size copper chromium contact material as claimed in claim 1 wherein, The method for oil removing treatment is: S1-1: immerse the copper-chromium contact in the oil removing agent for 2-3 min, then increase the temperature to 70-80 °C, add 0.6-0.8% boric acid solution by weight of the oil removing agent to adjust the pH to 6-8 every time the temperature is increased by 5-10 °C, the molar concentration of the boric acid solution is 0.1-0.3 mol / L, and the process is repeated until the temperature is increased to the end; S1-2: after the temperature is increased to the required temperature, keep the temperature, and when the pH of the oil removing agent with the boric acid solution decreases by 1 from 10.5, the keeping time is gradually increased by 1-3 min / pH from the initial 5-10 min; The oil removing agent comprises, by weight, 4-5% polyethylene glycol octylphenyl ether, 3-5% phosphate ester salt, 2-4% anhydrous sodium silicate, 2-4% sodium pyrophosphate, 4-6% dipropylene glycol methyl ether, 0.5-1.5% sodium o-phenylphenol, and the balance of water.

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