A manufacturing process of chromium bronze contact finger profile for high voltage switch

Abstract

The invention discloses a manufacturing process of a chromium bronze contact finger profile for a high-voltage switch, comprising S1, preparing an upward chromium bronze rod, S1-1, weighing 0.6-1.2% of Cr and the remainder of Cu by weight for batching; S1-2, adding the batching in S1-1 into a graphite crucible of an upward continuous casting furnace for melting, and maintaining the solution temperature at 1150-1350° C.; S1-3, performing upward continuous casting on the solution obtained in step S1-2 by a vertical continuous casting machine to obtain an upward cast chromium bronze rod, and then The upward cast chrome bronze rod is coiled by a coiler to obtain a coiled chrome bronze rod; S2, continuous extrusion, S3, cold drawing, S4, cut to length, S5, aging heat treatment, S6, post-processing for standby use. The present invention adopts continuous upward casting technology to prepare the chrome bronze rod, and the cast rod is directly stretched into a coil through the subsequent coiling step, which not only has the advantages of smooth appearance and round surface, but also can ensure the production of large length, while taking into account the subsequent processing equipment, effectively improving the manufacturing efficiency of the chrome bronze feeler profile.

Description

Technical Field

[0001] The invention relates to the technical field of high-voltage switches, and in particular to a manufacturing process of a chromium bronze contact finger profile for a high-voltage switch. Background Art

[0002] High-voltage switch refers to an electrical appliance with a rated voltage of 35kv or above, which is mainly used to open and close the conductive circuit. The contact finger is an important part of the clutch mechanism of this high-voltage switch, which is mainly used for the electrical contact between two relatively moving conductors. The characteristics of the contact finger directly affect the functional realization of the high-voltage switch.

[0003] Chromium bronze has high conductivity, high wear resistance and moderate mechanical properties. It is the main material for producing high-voltage switch contacts. Contact profiles can be used to produce high-voltage switch contacts. Most existing manufacturers use general semi-continuous casting to prepare raw materials, which has low production efficiency and low material utilization rate. Then, profiles are obtained by hot extrusion. Due to the uneven deformation during the hot extrusion process, the mechanical properties and metallographic structure consistency of the manufactured profiles are low, and the production process consumes a lot of energy. The surface quality of the profiles after hot extrusion is unstable, and there are many defects such as surface inclusions, peeling, and extrusion lines. The processing process is complicated and affects the product quality. In addition, the tail of the profile produced by the hot extrusion method will inevitably produce extrusion tail defects, which can only be minimized by the process but not completely solved. The existence of tail shrinkage defects destroys the density and continuity of the material, seriously affects the performance of the material, and is generally removed by naked eye and ultrasonic flaw detection. However, due to the irregular and unstable defects, there are detection blind spots, there is a risk of unidentified, and it cannot be pressed together in subsequent processing. There is a certain quality risk in the product, which may cause economic losses to subsequent enterprises. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a manufacturing process of a chromium bronze contact finger profile for a high voltage switch.

[0005] The technical solution of the present invention is: a manufacturing process of a chromium bronze contact finger profile for a high-voltage switch, comprising the following steps:

[0006] S1. Preparation of upper chrome bronze rod

[0007] S1-1. According to the weight percentage, 0.6-1.2% of Cr and the balance of Cu are weighed for mixing; Cr is added in the form of Cr cored wire, and Cu is added in the form of oxygen-free Cu rod; the chromium content should be neither too high nor too low. If the chromium content is too low, it will affect its mechanical properties, and if it is too high, it will cause cracks on the surface of the cast rod;

[0008] S1-2, adding the ingredients in S1-1 into the graphite crucible of the upper continuous casting furnace to melt, and maintaining the solution temperature at 1150-1350°C; if the casting temperature is too low, the fluidity of the melt will deteriorate, and there will be defects in the upper casting rod; if the casting temperature is too high, chromium will be easily oxidized, and the chromium content will also be difficult to control;

[0009] S1-3, the solution obtained in step S1-2 is continuously casted upward by a vertical continuous casting machine to obtain an upward cast chrome bronze rod; the upward cast chrome bronze rod is then coiled by a coiling machine to obtain a coiled chrome bronze rod, and the coil diameter is 1600-2400 mm; during the casting process, samples are taken from the furnace every 2 hours to detect the chemical composition, and samples are taken from the head and tail of the upward cast chrome bronze rod at the beginning and end of the casting to detect the chemical composition; the coiling can ensure the production of a large length, and the coil diameter is 1600-2400 mm, which ensures the production efficiency while taking into account the subsequent processing equipment;

[0010] S2, continuous extrusion

[0011] The extrusion die preheated at 300-500° C. for 20-30 minutes is loaded into the extrusion die cavity, the coiled chrome bronze rod obtained in step S1-3 is uncoiled by an uncoiler and fed into the extrusion die cavity, and the uncoiled chrome bronze rod is continuously extruded by a continuous extruder to obtain a chrome bronze finger extrusion profile; the continuous extrusion parameters are: increasing the spindle speed to 5-15 r / min, the extrusion temperature to 500-700° C., the extrusion ratio to 6-10, and the extrusion time to 30-90 minutes;

[0012] S3, cold drawing

[0013] The chrome bronze contact finger extruded profile obtained in step S2 is subjected to one to two cold drawing processes to obtain a chrome bronze contact finger drawn profile;

[0014] S4, Cut to length

[0015] The chrome bronze contact finger drawing profile obtained in step S3 is sawn into a fixed length according to the demand to obtain a chrome bronze contact finger profile with a fixed size;

[0016] S5. Aging heat treatment

[0017] Performing aging heat treatment on the chrome bronze finger contact profile obtained in step S4 under the action of a protective atmosphere, then cooling it to room temperature with the furnace, and sampling and testing the chrome bronze finger contact profile after the aging heat treatment;

[0018] S6, post-processing standby

[0019] The chromium bronze contact finger profile that has been tested and meets the manufacturing requirements is post-processed and subjected to finished product inspection to obtain the chromium bronze contact finger profile for the high-voltage switch; the standard for meeting the manufacturing requirements is that both the electrical conductivity and the mechanical properties meet the manufacturing requirements.

[0020] Further, in step S1-3, the upward continuous casting parameters are: the continuous casting speed in the length direction of the casting rod is 300-650 mm / min, and the diameter of the upward continuous casting chromium copper rod is 25-30 mm;

[0021] Note: The lifting speed should not be too fast or too slow. Too fast lifting speed will lead to a decrease in product quality, while too slow lifting speed will lead to a decrease in production efficiency.

[0022] Further, in step S2, the continuous extrusion process is as follows: the unrolled chromium bronze rod is continuously fed into the extrusion die cavity through an extrusion wheel, and extruded from the extrusion die after recrystallization; then cooled through a cooling water tank, and after the chromium bronze rod is cooled to room temperature, it is wound on the I-shaped wheel through a winder; finally, 99.9%wt nitrogen is used to purge the surface of the chromium bronze rod for 5 to 10 minutes;

[0023] Note: Cooling in a water tank can reduce the material temperature to near room temperature to ensure that the material does not oxidize at high temperatures. There is no requirement for cooling time, as long as it passes through a cooling water tank. The purging treatment can quickly dry the copper rod surface, prevent the residual moisture on the material surface from oxidizing, and also clean the surface of the chrome bronze rod.

[0024] Furthermore, in step S3, the cold deformation amount of a single cold drawing is 10-15%, and the cumulative cold deformation amount is 15-35%;

[0025] Note: Experiments have shown that more than 10% can ensure that the profile is fully deformed, and within 15%, the profile will not be torn. When the cumulative cold deformation exceeds 35%, the internal structure of the chromium-containing bronze profile will become uneven, so the cumulative cold deformation should be controlled within 35%.

[0026] Furthermore, in step S4, the sizing sawing process is: firstly, the chrome bronze contact finger profile is sized according to the length standard and the cross-sectional size standard of the high-voltage switch contact finger, and then the chrome bronze contact finger profile is sawed by a sawing process, and the processing is cooled by a coolant at the same time to maintain the processing temperature at 20-25°C;

[0027] Note: During the sawing process, the guide strip is cooled to between 20 and 25°C by coolant to prevent the guide strip from heating up due to processing and affecting product quality.

[0028] Furthermore, the coolant comprises the following components in percentage by mass: 15-25% of diethylene glycol, 0.01-0.2% of corrosion inhibitor, 0.5-1.5% of bamboo bleaching liquid, 1-3% of defoaming agent and the remainder of deionized water; the corrosion inhibitor is formed by mixing tolyltriazole and sodium hydroxide in a mass ratio of 1:1, and the defoaming agent is formed by mixing polyphenylene ether and ethyl 3-ethoxypropionate in a mass ratio of 1:1;

[0029] The preparation process of the bamboo bleaching liquid is as follows: soaking the bamboo in a 1-3wt.% bleaching powder solution for 50-70 minutes, taking out the bamboo and putting it in an acid solution of 5-7wt.% acetic acid and 0.5-1.5wt.% citric acid mixed in a ratio of 1:1, boiling at 80-100°C for 30-50 minutes, taking out the bamboo and washing it with clean water for 3-5 times, rinsing off the liquid attached to the bamboo and collecting it in a container bottle, and sealing it;

[0030] Description: Tolyltriazole is adsorbed on the metal surface to form a very thin film, which protects the chrome bronze from corrosion by harmful media in the atmosphere and water, and does not affect the quality of the conductor. The corrosion inhibitor prepared by mixing sodium hydroxide and tolyltriazole can effectively protect the chrome bronze contact finger profile, prevent or slow down the corrosion of the material, and remove the excess acid solution in the bamboo bleaching liquid. The bamboo bleaching liquid added to the coolant prepared according to the above ingredients not only has the cooling function, but also can degrease the surface of the chrome bronze contact finger profile, and the drying speed is fast, which is convenient for subsequent aging heat treatment.

[0031] Furthermore, in step S5, the process parameters of the aging heat treatment are: heating the temperature to 400-550°C at a heating rate of 5-10°C / min, and keeping the temperature for 2-6h;

[0032] Explanation: The experimental results show that aging treatment within the above temperature range can eliminate residual stress in the chrome bronze finger contact components that have been cold drawn and cut to length, and stabilize the structure and size of the chrome bronze finger contact profiles.

[0033] Further, in step S6, the post-processing process includes the following steps:

[0034] S6-1. Polishing

[0035] The chrome bronze finger profile obtained in step S5 is polished by a mechanical polisher until the surface roughness of each part reaches 1.5 to 3 μm;

[0036] S6-2, Artificial Cold Straightening

[0037] The chrome bronze finger profile obtained in step S6-1 is placed on a straightening platform, and then manually straightened from both ends of the chrome bronze finger profile toward the center to a desired shape using a plastic hammer at room temperature;

[0038] Note: Cold straightening can effectively adjust the defects in the shape of chrome bronze contact finger profiles. Mechanical polishing in advance can effectively improve the quality of the profiles and avoid surface scratches that affect the quality of the finished product.

[0039] Furthermore, in step S6, the finished product inspection step is: sampling and testing the finished product for dimensional tolerance, appearance, chemical composition, electrical conductivity, hardness, strength, and elongation; wherein the chemical composition is based on the chemical composition of the cast rod in step S1-1, and the electrical conductivity, hardness, strength, and elongation are based on the test results after aging heat treatment in step S5;

[0040] Note: The conductivity and mechanical properties of the tactile finger profiles that have undergone aging heat treatment are sampled and tested. The tactile finger profiles whose conductivity and mechanical properties meet expectations can be transferred to the next process; the tactile finger profiles whose conductivity is lower than expected are returned to the furnace for aging heat treatment, and the heat treatment process parameters are determined according to the test results; the tactile finger profiles whose conductivity is higher than expected and whose mechanical properties are lower than expected are directly scrapped. Random inspections during the production process can eliminate waste products and discover problems in a timely manner, which is conducive to improving production efficiency and product qualification rate; the above-mentioned inspection contents can effectively measure the various properties of the finished product, thereby effectively improving the preparation efficiency.

[0041] The beneficial effects of the present invention are:

[0042] (1) The present invention adopts continuous upward casting technology to prepare the chrome bronze rod, and directly stretches the cast rod into a coil through a subsequent coiling step, which not only has the advantages of smooth appearance and round surface, but also can ensure the production of large lengths, while taking into account the subsequent processing equipment and effectively improving the manufacturing efficiency of the chrome bronze feeler profile.

[0043] (2) The present invention adds a specific coolant during the cut-to-length sawing process so that the processing temperature can be controlled. On the one hand, it can prevent the guide bar from affecting the product quality due to the temperature rise during processing. On the other hand, it can also degrease the surface of the chrome bronze contact finger profile to protect the chrome bronze from corrosion by harmful media in the atmosphere and water, without affecting the quality of the guide bar, and facilitate subsequent aging heat treatment.

[0044] (3) The coolant prepared by the present invention contains bamboo bleaching liquid, which can effectively reduce the temperature and has a fast drying speed, slowing down corrosion, and is convenient for subsequent aging heat treatment. The addition of bamboo bleaching liquid can also degrease the surface of the chrome bronze finger contact profile, thereby effectively improving the manufacturing qualification rate of the chrome bronze finger contact profile. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0046] Example 1

[0047] A manufacturing process of a chromium bronze contact finger profile for a high-voltage switch comprises the following steps:

[0048] S1. Preparation of upper chrome bronze rod

[0049] S1-1. According to the weight percentage, 0.85% of Cr and the balance of Cu are weighed for mixing; Cr is added in the form of Cr cored wire, and Cu is added in the form of oxygen-free Cu rod;

[0050] S1-2, adding the ingredients in S1-1 into the graphite crucible of the upward continuous casting furnace to melt, and maintaining the solution temperature at 1300°C;

[0051] S1-3, the solution obtained in step S1-2 is subjected to upward continuous casting by a vertical continuous casting machine to obtain an upward cast chromium bronze rod; the upward cast chromium bronze rod is then coiled by a coiling machine to obtain a coiled chromium bronze rod, and the coiling diameter is 2000 mm; wherein the upward continuous casting parameters are: the continuous casting speed in the length direction of the casting rod is 600 mm / min, and the diameter of the upward continuous cast chromium bronze rod is 28 mm;

[0052] S2, continuous extrusion

[0053] The extrusion die preheated at 500° C. for 20 minutes is loaded into the extrusion die cavity, the coiled chrome bronze rod obtained in step S1-3 is unrolled by an unwinder and fed into the extrusion die cavity, and the continuous extruder is turned on to continuously extrude the unrolled chrome bronze rod to obtain a chrome bronze finger extrusion profile; the continuous extrusion parameters are: increasing the spindle speed to 10 r / min, the extrusion temperature is 600° C., the extrusion ratio is 8, and the extrusion time is 60 minutes; wherein the continuous extrusion process is: continuously feeding the unrolled chrome bronze rod into the extrusion cavity by an extrusion wheel, and extruding it from the extrusion die after recrystallization; then cooling it through a cooling water tank, and winding the chrome bronze rod on an I-shaped wheel after it cools to room temperature through a winding machine; then using 99.9%wt nitrogen to purge the surface of the chrome bronze rod for 8 minutes; obtaining the cross-sectional dimensions of the chrome bronze rod extrusion profile; the detection standard is: width 21.5-22.5 mm, height 3.5-4.5 mm;

[0054] S3, cold drawing

[0055] The chrome bronze contact finger extruded profile obtained in step S2 is subjected to two cold drawing processes to obtain a chrome bronze contact finger drawn profile; the cross-sectional dimensions of the chrome bronze contact finger drawn profile are obtained; the inspection standard is: width 19.5-20.5 mm, height 2.5-3.5 mm, length 598-602 mm, the profile cross-section is rectangular, wherein the cold deformation amount of a single cold drawing pass is 12%, and the cumulative cold deformation amount is 24%;

[0056] S4, Cut to length

[0057] The chrome bronze contact finger drawing profile obtained in step S3 is cut into fixed-size pieces according to the requirements to obtain a chrome bronze contact finger profile with a fixed size; wherein the fixed-size sawing process is: firstly, the chrome bronze contact finger profile is cut into fixed-size pieces according to the standard of the length and the cross-sectional size of the high-voltage switch contact finger, and then the chrome bronze contact finger profile is cut into pieces by sawing, and the processing is cooled by a coolant at the same time to maintain the processing temperature at 22°C;

[0058] The coolant comprises the following components by mass percentage: 20% of diethylene glycol, 0.1% of corrosion inhibitor, 1% of bamboo bleaching liquid, 2% of defoamer and the balance of deionized water; the corrosion inhibitor is prepared by mixing tolyltriazole and sodium hydroxide in a mass ratio of 1:1, and the defoamer is prepared by mixing polyphenylene ether and ethyl 3-ethoxypropionate in a mass ratio of 1:1;

[0059] The preparation process of bamboo bleaching liquid is as follows: soak bamboo in a 2wt.% bleaching powder solution for 60 minutes, take it out and put it in an acid solution of 6wt.% acetic acid and 1wt.% citric acid mixed in a ratio of 1:1, cook it at 90°C for 40 minutes, take out the bamboo and wash it with clean water for 4 times, remove the liquid attached to the bamboo and collect it in a container bottle, and seal it;

[0060] S5. Aging heat treatment

[0061] The chrome bronze finger contact profile obtained in step S4 is subjected to aging heat treatment under the action of a protective atmosphere, and then cooled to room temperature with the furnace, and the chrome bronze finger contact profile obtained after aging heat treatment is sampled for testing; wherein, the process parameters of the aging heat treatment are: heating the temperature to 500°C at a heating rate of 8°C / min, and the holding time is 4h; the conductivity of the conductor bar of the chrome bronze profile after aging heat treatment is tested at a sampling frequency of 100%, and the strength and hardness of the conductor bar are tested at a sampling intensity of 1%; the finger contact profile with a conductivity lower than expected is returned to the furnace for aging heat treatment, and the heat treatment process parameters are determined according to the test results; the finger contact profile with a conductivity higher than expected and a mechanical property lower than expected is directly scrapped;

[0062] S6, post-processing standby

[0063] The chrome bronze contact finger profile that has been tested and meets the manufacturing requirements is post-processed and the finished product is inspected to obtain the chrome bronze contact finger profile for the high-voltage switch; wherein the post-processing process includes the following steps:

[0064] S6-1. Polishing

[0065] The chrome bronze finger profile obtained in step S5 is polished by a mechanical polisher until the surface roughness of each part reaches 2 μm;

[0066] S6-2, Artificial Cold Straightening

[0067] The chrome bronze finger profile obtained in step S6-1 is placed on a straightening platform, and then manually straightened from both ends of the chrome bronze finger profile toward the center to a desired shape using a plastic hammer at room temperature;

[0068] The finished product inspection steps are: sampling and testing the dimensional tolerance, appearance, chemical composition, electrical conductivity, hardness, strength and elongation of the finished product; the chemical composition is based on the chemical composition of the cast rod in step S1-1, and the electrical conductivity, hardness, strength and elongation are based on the test results after aging heat treatment in step S5.

[0069] Example 2

[0070] Different from Example 1, in S1-1, 0.6% of Cr and the balance of Cu are weighed for mixing by weight percentage.

[0071] Example 3

[0072] Different from Example 1, in S1-1, 1.2% of Cr and the balance of Cu are weighed for mixing by weight percentage.

[0073] Example 4

[0074] Different from Example 1, in S1-2, the ingredients in S1-1 are added to the graphite crucible of the upward continuous casting furnace for melting, and the solution temperature is maintained at 1150°C.

[0075] Example 5

[0076] Different from Example 1, in S1-2, the ingredients in S1-1 are added to the graphite crucible of the upward continuous casting furnace for melting, and the solution temperature is maintained at 1350°C.

[0077] Example 6

[0078] Different from Example 1, in S1-3, the coil diameter is 1600 mm; wherein, the upward continuous casting parameters are: the continuous casting speed in the length direction of the casting rod is 300 mm / min, and the diameter of the upward continuous casting chromium copper rod is 25 mm.

[0079] Example 7

[0080] Different from Example 1, in S1-3, the coil diameter is 2400 mm; wherein, the upward continuous casting parameters are: the continuous casting speed in the length direction of the casting rod is 650 mm / min, and the diameter of the upward continuous casting chromium copper rod is 30 mm.

[0081] Example 8

[0082] Different from Example 1, in S2, the continuous extrusion parameters are: the spindle speed is increased to 5 r / min, the extrusion temperature is 500° C., the extrusion ratio is 6, and the extrusion time is 30 min.

[0083] Example 9

[0084] Different from Example 1, in S2, the continuous extrusion parameters are: increasing the spindle speed to 15 r / min, the extrusion temperature is 700° C., the extrusion ratio is 10, and the extrusion time is 90 min.

[0085] Example 10

[0086] Different from Example 1, in S3, the cold deformation amount of a single cold drawing pass is 10%, and the cumulative cold deformation amount is 20%.

[0087] Embodiment 11

[0088] Different from Example 1, in S3, the cold deformation amount of a single cold drawing pass is 15%, and the cumulative cold deformation amount is 30%.

[0089] Example 12

[0090] Different from Example 1, in S4, the processing is cooled by coolant at the same time to maintain the processing temperature at 20°C.

[0091] Embodiment 13

[0092] Different from Example 1, in S4, the processing is cooled by coolant at the same time to maintain the processing temperature at 25°C.

[0093] Embodiment 14

[0094] Different from Example 1, in S4, the coolant includes the following components in terms of mass ratio: 15% of diethylene glycol, 0.01% of corrosion inhibitor, 0.5% of bamboo bleaching liquid, 1% of defoaming agent, and the remainder of deionized water; the corrosion inhibitor is formed by mixing tolyltriazole and sodium hydroxide in a mass ratio of 1:1, and the defoaming agent is formed by mixing polyphenylene ether and ethyl 3-ethoxypropionate in a mass ratio of 1:1;

[0095] The preparation process of bamboo bleaching liquid is as follows: soak bamboo in a 1wt.% bleaching powder solution for 70 minutes, take it out and put it in an acid solution of 5wt.% acetic acid and 0.5wt.% citric acid mixed in a ratio of 1:1, cook it at 80°C for 30 minutes, take out the bamboo and wash it with clean water for 3 times, remove the liquid attached to the bamboo and collect it in a container bottle, and seal it;

[0096] Embodiment 15

[0097] Different from Example 1, in S4, the coolant includes the following components in terms of mass ratio: 25% of diethylene glycol, 0.2% of corrosion inhibitor, 1.5% of bamboo bleaching liquid, 3% of defoaming agent and the remainder of deionized water; the corrosion inhibitor is formed by mixing tolyltriazole and sodium hydroxide in a mass ratio of 1:1, and the defoaming agent is formed by mixing polyphenylene ether and ethyl 3-ethoxypropionate in a mass ratio of 1:1;

[0098] The preparation process of bamboo bleaching liquid is as follows: soak the bamboo in a 3wt.% bleaching powder solution for 50 minutes, take it out and put it into an acidic solution of 7wt.% acetic acid and 1.5wt.% citric acid mixed in a ratio of 1:1, cook it at 100°C for 50 minutes, then take out the bamboo and wash it with clean water for 5 times, rinse off the liquid attached to the bamboo and collect it in a container bottle, and seal it.

[0099] Example 16

[0100] Different from Example 1, in S5, the process parameters of the aging heat treatment are: heating the temperature to 400° C. at a heating rate of 5° C. / min and keeping the temperature for 6 h.

[0101] Embodiment 17

[0102] Different from Example 1, in S5, the process parameters of the aging heat treatment are: heating the temperature to 550° C. at a heating rate of 10° C. / min and keeping the temperature for 2 h.

[0103] Comparison Example

[0104] Comparative Example 1: Different from Example 1, in S5, the process parameters of the aging heat treatment are: heating the temperature to 300°C at a heating rate of 8°C / min and keeping the temperature for 4h.

[0105] Comparative Example 2: Different from Example 1, in S1-3, the solution obtained in step S1-2 is subjected to upward continuous casting by a die casting method to obtain an upward cast chromium bronze rod.

[0106] Comparative Example 3: Different from Example 1, in S2, the continuous extrusion parameters are: increasing the spindle speed to 10 r / min, the extrusion temperature is 600°C, the extrusion ratio is 3, and the extrusion time is 60 min.

[0107] Comparative Example 4: Different from Example 1, the coolant is a commercially available 99.9% ethylene glycol stock solution.

[0108] Experimental example

[0109] The data obtained from the testing of the chromium bronze finger profiles prepared in Examples 1 to 17 and Comparative Examples 1 to 4 were sorted out, and the average values ​​of the parameters were taken for exploration;

[0110] 1. The effects of different Cr and Cu contents and different aging treatment parameters on the size specifications of chrome bronze contact finger profiles were investigated. The results are shown in the following table:

[0111] Table 1. Dimensions

[0112]

[0113]

[0114] Conclusion: From the data in Table 1, it can be seen that different Cr and Cu contents have little effect on the size specifications of the chrome bronze contact finger profile. Aging treatment within the temperature range of 400-550°C can eliminate residual stress in the chrome bronze contact finger components that have been cold drawn and cut to size, stabilize the structure and size of the chrome bronze contact finger profile, and make the chrome bronze contact finger profile meet the manufacturing standards. Temperatures below the above value will cause the size of the chrome bronze contact finger profile to exceed the standard. From the above data, it can be seen that Example 1 is the optimal solution.

[0115] 2. Investigate the effect of upward continuous casting technology on the chemical composition of chromium bronze finger profiles. The results are shown in the following table:

[0116] Table 2. Chemical composition test results %

[0117] element Cu Cr Si Fe Pb Max. - 1.2 0.1 0.1 0.05 Min. 99.35 0.6 - - - Example 1 99.25 0.52 0.001 0.002 0.0005 Example 2 99.15 0.88 0.001 0.002 0.0005 Example 3 99.36 0.62 0.001 0.002 0.005 Comparative Example 2 99.1 0.76 0.005 0.003 0.006

[0118] Conclusion: From the data in Table 2, it can be seen that the chemical composition of the chrome bronze contact finger profiles prepared by the upward continuous casting technology can meet the standards and have high quality. Although the chemical composition of the chrome bronze contact finger profiles prepared by the die casting method in Control Example 2 can also meet the standards, it has the problems of high cost, complicated operation process, high labor intensity of workers and low production efficiency. Considering the comprehensive cost, the upward continuous casting technology can be used instead of die casting to effectively improve the production efficiency of the chrome bronze contact finger profiles, and Example 1 is the best solution.

[0119] 3. Investigate the effects of aging heat treatment, extrusion ratio parameters, and coolant composition on the electrical and mechanical properties of chromium bronze contact finger profiles. The results are shown in the following table:

[0120] Table 3. Electrical and mechanical properties

[0121]

[0122] Conclusion: From the data of Example 1, Examples 16-17 and Comparative Example 1 in Table 3, it can be seen that aging treatment in the temperature range of 400-550°C can eliminate residual stress of the chrome bronze contact finger components that have been cold drawn and cut to length, stabilize the structure of the chrome bronze contact finger profile, and effectively improve the performance of the chrome bronze contact finger profile; from the data of Examples 1-3, Example 8, Example 9 and Comparative Example 3, it can be seen that the extrusion ratio in Comparative Example 3 is less than 6, which will lead to a smaller deformation of the chrome bronze rod material, resulting in insufficient grain refinement, thereby reducing both electrical and mechanical properties; From the data of Examples 1 to 3, Example 14, Example 15 and Control Example 4, it can be obtained that the coolant prepared according to the present method has the functions of cooling and anti-corrosion and can also degrease the surface of the chrome bronze contact finger profile, and at the same time, the drying speed is fast, which is more convenient for subsequent aging heat treatment, and can effectively improve the various properties of the chrome bronze profile, while the coolant of Control Example 4 cannot efficiently remove impurities on the surface of the chrome bronze contact finger profile, resulting in a decrease in various properties of the finished product; therefore, it can be obtained that the manufacturing method of the present invention can prepare chrome bronze contact finger profiles with various properties that meet the requirements, and can be promoted for use.

Claims

1. A manufacturing process for chromium bronze contact finger profiles for high-voltage switches. It is characterized in that The following steps are involved: S1. Preparation of upper chrome bronze rod S1-1. According to the weight percentage, 0.6-1.2% of Cr and the balance of Cu are weighed for mixing; Cr is added in the form of Cr cored wire, and Cu is added in the form of oxygen-free Cu rod; S1-2, adding the ingredients in S1-1 into the graphite crucible of the upward continuous casting furnace to melt, and maintaining the solution temperature at 1150~1350℃; S1-3, performing upward continuous casting on the solution obtained in step S1-2 by a vertical continuous casting machine to obtain an upward cast chromium bronze rod; then coiling the upward cast chromium bronze rod by a coiling machine to obtain a coiled chromium bronze rod, wherein the coiling diameter is 1600-2400 mm; S2, continuous extrusion The extrusion die preheated at 300-500° C. for 20-30 minutes is loaded into the extrusion die cavity, the coiled chrome bronze rod obtained in step S1-3 is uncoiled by an uncoiler and fed into the extrusion die cavity, and the uncoiled chrome bronze rod is continuously extruded by a continuous extruder to obtain a chrome bronze contact finger extrusion profile; The continuous extrusion parameters are: increase the spindle speed to 5~15r / min, the extrusion temperature is 500~700℃, the extrusion ratio is 6~10, and the extrusion time is 30~90min; S3, cold drawing The chrome bronze contact finger extruded profile obtained in step S2 is subjected to one to two cold drawing processes to obtain a chrome bronze contact finger drawn profile; S4, Cut to length The chrome bronze contact finger drawing profile obtained in step S3 is cut into fixed-size pieces according to the requirements to obtain a chrome bronze contact finger profile with a fixed size; the cutting process is as follows: firstly, the chrome bronze contact finger profile is cut into fixed-size pieces according to the standard of the length and the cross-sectional size of the high-voltage switch contact finger, and then the chrome bronze contact finger profile is cut into pieces by sawing, and the processing is cooled by a coolant at the same time to maintain the processing temperature at 20-25°C; The coolant comprises the following components by mass percentage: 15-25% of diethylene glycol, 0.01-0.2% of corrosion inhibitor, 0.5-1.5% of bamboo bleaching liquid, 1-3% of defoaming agent and the balance of deionized water; the corrosion inhibitor is prepared by mixing tolyltriazole and sodium hydroxide in a mass ratio of 1:1, and the defoaming agent is prepared by mixing polyphenylene ether and ethyl 3-ethoxypropionate in a mass ratio of 1:1; The preparation process of the bamboo bleaching liquid is as follows: soaking the bamboo in a 1-3wt.% bleaching powder solution for 50-70 minutes, taking out the bamboo and putting it in an acid solution of 5-7wt.% acetic acid and 0.5-1.5wt.% citric acid mixed in a ratio of 1:1, boiling at 80-100°C for 30-50 minutes, taking out the bamboo and washing it with clean water for 3-5 times, rinsing off the liquid attached to the bamboo and collecting it in a container bottle, and sealing it; S5. Aging heat treatment Performing aging heat treatment on the chrome bronze finger contact profile obtained in step S4 under the action of a protective atmosphere, then cooling it to room temperature with the furnace, and sampling and testing the chrome bronze finger contact profile after the aging heat treatment; S6, post-processing standby The chrome bronze contact finger profile that has been tested and meets the manufacturing requirements is post-processed and subjected to finished product inspection to obtain the chrome bronze contact finger profile for the high-voltage switch.

2. A manufacturing process of a chromium bronze contact finger profile for a high-voltage switch according to claim 1, It is characterized in that In step S1-3, the upward continuous casting parameters are: the continuous casting speed in the length direction of the casting rod is 300-650 mm / min, and the diameter of the upward continuous casting chromium-copper rod is 25-30 mm.

3. A manufacturing process of a chromium bronze contact finger profile for a high-voltage switch according to claim 1, It is characterized in that In step S2, the continuous extrusion process is as follows: the unrolled chromium bronze rod is continuously fed into the extrusion die cavity through an extrusion wheel, and extruded from the extrusion die after recrystallization; then cooled through a cooling water tank, and after the chromium bronze rod is cooled to room temperature, it is wound on the I-shaped wheel through a winder; finally, 99.9%wt nitrogen is used to purge the surface of the chromium bronze rod for 5 to 10 minutes.

4. A manufacturing process of a chromium bronze contact finger profile for a high voltage switch according to claim 1, It is characterized in that In step S3, the cold deformation amount of a single cold drawing is 10-15%, and the cumulative cold deformation amount is 15-35%.

5. A manufacturing process of a chromium bronze contact finger profile for a high-voltage switch according to claim 1, It is characterized in that In step S5, the process parameters of the aging heat treatment are: heating the temperature to 400-550°C at a heating rate of 5-10°C / min, and keeping the temperature for 2-6h.

6. A manufacturing process of a chromium bronze contact finger profile for a high voltage switch according to claim 1, It is characterized in that In step S6, the post-processing process includes the following steps: S6-1. Polishing The chrome bronze finger profile obtained in step S5 is polished by a mechanical polisher until the surface roughness of each part reaches 1.5-3 μm; S6-2, Artificial Cold Straightening The chrome bronze finger profile obtained in step S6-1 is placed on a straightening platform, and then manually straightened from both ends of the chrome bronze finger profile toward the center to a desired shape using a plastic hammer at room temperature.

7. A manufacturing process of a chromium bronze contact finger profile for a high voltage switch according to claim 1, It is characterized in that In step S6, the finished product inspection step is: sampling and testing the dimensional tolerance, appearance, chemical composition, electrical conductivity, hardness, strength, and elongation of the finished product; wherein the chemical composition is based on the chemical composition of the cast rod in step S1-1, and the electrical conductivity, hardness, strength, and elongation are based on the test results after the aging heat treatment in step S5.

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