Preparation process of copper-clad steel product and vacuum arc-extinguishing chamber conducting rod prepared by method

Abstract

The invention relates to the field of metal composite materials, and provides a preparation technology of a copper-clad steel product and a vacuum arc-extinguishing chamber conducting rod prepared through the method, and the technology comprises the following steps that S1, the surfaces of a steel core and a copper pipe are pretreated; s2, treatment of the welding flux; s3, smearing of solder paste and winding of solder wires are conducted; s4, assembling the steel core and the copper pipe; and S5, vacuum sintering. According to the invention, the defects in the prior art are overcome, the design is reasonable, the process is reliable, the bonding strength of the copper layer and the steel core can be improved, and meanwhile, the product has excellent conductivity and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of metal composite materials, and is particularly applicable to fields such as power transmission, communication, and grounding systems that have high requirements for conductivity and mechanical strength. Specifically, it relates to a preparation process for copper-clad steel products and the conductive rod of a vacuum interrupter prepared by this method. Background Technology

[0002] In many industries today, there is a growing demand for materials that combine good electrical conductivity with high mechanical strength. While traditional pure copper has excellent electrical conductivity, its relatively low mechanical strength makes it prone to deformation and breakage in applications requiring high tensile or compressive stresses, limiting its applications. Pure steel, on the other hand, while possessing high mechanical strength, has far lower electrical conductivity than copper, failing to meet the requirements for low resistance and high conductivity efficiency.

[0003] Copper-clad steel (CCL) is a composite material that combines the excellent electrical conductivity of copper with the high strength of steel. Existing CCL preparation processes mainly include electroplating, cladding welding, and continuous casting. However, electroplating results in limited bonding strength between the copper layer and the steel core, leading to copper layer detachment during subsequent processing or use. While cladding welding can improve bonding strength, it is complex, inefficient, and costly. Continuous casting requires sophisticated equipment and struggles to precisely control the interface quality between the copper layer and the steel core, resulting in inconsistent product quality. These problems severely restrict the application and development of CCL in a wider range of fields. Therefore, developing a new process to overcome these shortcomings and produce high-performance, low-cost, and stable-quality CCL is of significant practical importance. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for copper-clad steel products, so as to improve the bonding strength between the copper layer and the steel core, while ensuring that the product has excellent electrical conductivity and mechanical properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A manufacturing process for copper-clad steel products includes the following steps:

[0007] S1. Surface pretreatment of steel core and copper tube: Clean the steel core and copper tube respectively to remove surface impurities;

[0008] S2. Solder processing: Mix solder powder and nitrocellulose solution at a mass ratio of 4:1 and stir evenly to obtain solder paste;

[0009] S3. Applying solder paste and winding solder wire: Apply solder paste evenly to the entire sidewall of the steel core and wind solder wire at the upper end of the steel core.

[0010] S4. Assembly of steel core and copper tube: Insert the steel core coated with solder paste and solder wire into the copper tube, and place the solder wire in the tapered opening at the upper end of the copper tube cavity.

[0011] S5. Vacuum sintering: The composite steel core-copper tube is placed in a vacuum sintering furnace for vacuum sintering to obtain copper-clad steel products.

[0012] Furthermore, the process also includes the following steps:

[0013] S6. The copper-clad steel products after being taken out of the furnace are sanded, turned, drilled and tapped on a lathe to finally process them into the required shape. The turning includes removing the vertical height area where the tapered opening is located.

[0014] Furthermore, the steel core material is 304 stainless steel, 40CrNiMo alloy steel, or 42CrMo alloy steel;

[0015] The copper tube is made of oxygen-free copper with a purity of not less than 99.9%.

[0016] Furthermore, the cleaning of the steel core includes the following steps:

[0017] Degreasing and cleaning: The steel core to be cleaned is washed with a detergent solution;

[0018] Acid cleaning involves cleaning the degreased steel core with an acidic solution.

[0019] Neutralization treatment involves cleaning the acid-treated steel core with a neutralization solution, rinsing it thoroughly with deionized water after neutralization, and then drying it for later use.

[0020] Furthermore, if the steel core material is 304 stainless steel, the raw materials of the pickling solution, by mass percentage, are 8%~10% hydrofluoric acid, 25%~28% nitric acid, and the remainder is water; the pickling conditions are as follows: temperature 70℃~74℃, soaking and cleaning for 10~15 minutes.

[0021] If the steel core material is alloy steel 40CrNiMo or alloy steel 42CrMo, the raw materials of the pickling solution, by volume, are: 60 parts water, 20-25 parts hydrogen peroxide, and 15-20 parts oxalic acid.

[0022] The raw materials for the pickling solution of the copper tube, according to the following proportions, are: 1000ml water, 120g chromic anhydride, and 30ml sulfuric acid; the pickling conditions are: temperature 70~80℃, pickling time 3~5 minutes.

[0023] The neutralization solution for both the steel core and the copper tube is an ammonia solution with a mass percentage of 2-5%, which is used for soaking and neutralizing for 1-3 minutes.

[0024] Furthermore, the conditions for vacuum sintering are as follows:

[0025] The room temperature is raised to 450℃ and maintained for 45 minutes; then held at 450℃ for 30 minutes; the temperature is raised from 450℃ to 700℃ and maintained for 1 hour; the temperature is raised from 700℃ to 850℃ and maintained for 50 minutes; then held at 850℃ for 40 minutes; the temperature is raised from 850℃ to 900℃ and maintained for 30 minutes; then held at 900℃ for 45 minutes and the power is turned off; after cooling to 450℃, nitrogen is added and the temperature is rapidly cooled; the temperature is then lowered to ≤40℃ before the furnace is removed from the oven.

[0026] Furthermore, the steel core and copper tube are assembled using a steel core pressing device to press the upright steel core into the copper tube.

[0027] Furthermore, the steel core pressing device includes a fixed base, an upper pressing assembly, a movable base, and a lower pressing assembly arranged from top to bottom above the fixed base, as well as a pressing drive unit for the upper pressing assembly and the lower pressing assembly to move vertically.

[0028] The fixed base is provided with vertical guide members on both sides, and the upper end face of the fixed base is provided with a central through hole and a number of clamping blocks distributed around the central through hole.

[0029] The upper pressing assembly includes an upper positioning block, an upper bearing plate, and an upper disengagement drive unit. The upper positioning block is connected to the output end of the upper disengagement drive unit, the upper disengagement drive unit is mounted on the upper bearing plate, and the upper bearing plate is slidably supported on guide members on both sides.

[0030] (Whereinafter, the upper support plate includes a first upper support plate and a second upper support plate arranged in parallel from bottom to top; the upper positioning block is installed on the lower part of the first upper support plate; and the upper disengagement drive unit is installed on the lower part of the second upper support plate, with its output end connected to the first upper support plate;)

[0031] The lower pressing assembly includes a lower positioning block, a lower push rod, a lower bearing plate, and a lower disengagement drive unit. The lower positioning block is disposed in a graphite tray and is inserted into the lower push rod. The lower push rod is connected to the output end of the lower disengagement drive unit. The lower disengagement drive unit is mounted on the lower bearing plate. The lower bearing plate is slidably supported on guide members on both sides. The lower bearing plate and the upper bearing plate are connected on both sides by a synchronous rod.

[0032] (Wherein, the lower support plate includes a first lower support plate and a second lower support plate arranged parallel to each other from top to bottom; the lower push rod is installed on the upper part of the first lower support plate; the lower disengagement drive unit is installed on the upper part of the second lower support plate and its output end is connected to the first lower support plate; the two sides of the second upper support plate and the second lower support plate are fixedly connected by a synchronizing rod; the two sides of the first upper support plate and the first lower support plate are respectively slidably engaged with the synchronizing rod;)

[0033] The steel core has an upper positioning hole and a lower positioning hole at its two axial ends, respectively. The lower end of the upper positioning block has an upper positioning protrusion that mates with the upper positioning hole, and the upper end of the lower positioning block has a lower positioning protrusion that mates with the lower positioning hole.

[0034] The graphite tray has an annular protrusion on its upper surface, and a stepped through hole is provided on the inner side of the annular protrusion. The lower push rod can pass through the stepped through hole from bottom to top, and the lower positioning block can be completely housed in the stepped through hole.

[0035] The press-fitting drive unit is mounted on a fixed base and its output end is connected to the lower support plate.

[0036] Preferably, an expansion joint is coaxially mounted on the upper end of the lower push rod, and a plurality of expansion blocks are elastically connected to the side of the expansion joint.

[0037] The expansion joint has several guide grooves on its side. The expansion block is slidably disposed in the guide groove. A pair of guide bolts distributed from top to bottom pass through the expansion block and are threadedly connected to the side wall of the guide groove. A spring is sleeved on the guide bolt. The two ends of the spring abut against the side wall of the expansion block and the guide groove, respectively.

[0038] Furthermore, the assembly process of the steel core and copper tube is as follows:

[0039] S1' Place the center positioning sleeve on the lower top rod and pass it upward through the center hole of the movable base. Then support the graphite tray on the movable base. Specifically, the graphite tray is placed outside the center positioning sleeve and its circumference is clamped by the lower V-shaped block. Then remove the center positioning sleeve.

[0040] S2', The copper tube is supported on the graphite tray, and the annular boss of the graphite tray is inserted into the copper tube, and its circumference is clamped by the upper V-shaped block.

[0041] S3' Start the press-fitting drive unit, drive the lower push rod upward through the copper tube, and then manually put the lower positioning block on the expansion joint (the expansion joint is inserted into the positioning hole at the bottom of the lower positioning block and its expansion block is pressed against the lower positioning block by the spring). Then place the steel core on the lower positioning block, and insert the lower positioning protrusion of the lower positioning block into the lower positioning hole of the steel core. Finally, start the upper disengagement drive unit, press the upper positioning block down separately until its upper positioning protrusion is inserted into the upper positioning hole of the steel core, so as to realize the vertical press-fitting and fixing of the steel core.

[0042] S4' The press-fitting drive unit drives the lower press-fitting assembly, the upper press-fitting assembly, and the steel core to move down together until the steel core is fully inserted into the copper tube.

[0043] The present invention also provides a vacuum interrupter conductive rod prepared by the above method.

[0044] This invention provides a manufacturing process for copper-clad steel products and a conductive rod for a vacuum interrupter prepared by this method, which has the following beneficial effects:

[0045] 1. Copper-clad steel products processed using the above process are less prone to copper grain growth, and "ice flowers" will not appear on the conductive connection surface. This enhances the bonding force between the copper and the steel core, avoiding common problems such as porosity, looseness, and cracks that may occur between the copper and the steel core during subsequent processing. At the same time, it greatly improves the mechanical properties of the copper-clad steel composite, precisely controls the dimensional accuracy of the product, and ensures the strength, conductivity, and thermal conductivity of the conductive rod material used in high-voltage vacuum interrupters.

[0046] 2. To ensure effective welding of the steel core and copper tube, on the one hand, a tapered opening is provided at the upper end of the copper tube cavity. Solder wire is wound around the upper end of the steel core and placed inside the tapered opening after assembly. The solder wire is fixed inside the tapered opening by mechanical tension after winding, ensuring a stable shape and preventing displacement or loss during assembly and handling. This ensures that the solder is concentrated in the tapered opening area during sintering. During sintering, the solder wire melts first to form a liquid solder "reservoir". Under the influence of capillary action and gravity, it flows directionally into the gap along the inclined surface of the tapered opening, filling from the top to the bottom and fusing with the original solder paste in the gap to form a continuous and dense weld. On the other hand, if the nitrocellulose solution in the solder paste evaporates and the air is not vented in time, bubbles and pores are easily formed at the junction of the tapered opening and the gap. Using solder wire with the same composition as the solder powder wound around the upper end of the steel core can effectively vent the air and is pure solder without flux, which can achieve a sufficient filling effect. Attached Figure Description

[0047] Figure 1 A schematic diagram of the assembly of copper-clad steel bars before vacuum sintering;

[0048] Figure 2 The rear face morphology of the copper-clad steel sheet after pressure testing;

[0049] Figure 3 Metallographic structures of cross-sections of copper and steel;

[0050] Figure 4 These are photographs of the copper and steel cross-sections after the sample was cut.

[0051] Figure 5 This is a schematic diagram of the steel core pressing device.

[0052] Figure 6 This is a schematic diagram of the structure of the steel core pressing device, which includes an upper positioning block, a steel core, a copper tube, a lower positioning block, a graphite tray, and a lower push rod.

[0053] Figure 7 A cross-sectional schematic diagram showing the cooperation of the upper positioning block, steel core, copper tube, lower positioning block, graphite tray and lower push rod in the steel core pressing device;

[0054] Figure 8 This is a schematic diagram of the structure of the expansion joint and expansion block in the steel core pressing device. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] 1. Raw material preparation:

[0058] Steel core: 304 stainless steel, diameter Ø30 0 / -0.1 The long bar has a length of 475±0.2mm. The outer surface of the long bar is roughened with a steel brush, and its roughness is Ra12.5. The end face of the stainless steel bar is free of burrs.

[0059] Regarding the surface roughness of the steel core, a suitable range is 8.0-12.5, which ensures sufficient mechanical interlocking force and solder wettability, guides the capillary flow of the solder, and guarantees uniform gap filling, while avoiding filling defects caused by excessive roughness. In the embodiments of this application, the value is taken as 12.5.

[0060] Copper tubing: 99.95% pure oxygen-free copper; outer diameter Ø65mm, inner diameter Ø30mm +1.0 / +0.05The upper end of the tube has a tapered opening with a depth of 20mm and a chamfer angle of 30 degrees, and the length of the copper tube is 475±0.2mm.

[0061] 2. Surface pretreatment of steel core and copper tube

[0062] (1) Surface pretreatment of steel core: Remove oxide scale, oil stains and other impurities from the surface of the steel core. Then, put the steel core into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., and boil it for 15 minutes or vibrate it with ultrasound for 30 minutes. Rinse it with deionized water to remove surface oil stains. Then, put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is as follows (by mass percentage): hydrofluoric acid: 10%, nitric acid: 25%, water: balance. The acid pickling temperature is 70℃, and the soaking time is 15 minutes to further remove surface impurities, improve the wettability of the steel core surface to the solder, and enhance the bonding force between the subsequent copper layer and the steel core. After acid pickling, put the steel core into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution (by mass percentage). The neutralization time is 3 minutes. After neutralization, rinse it with deionized water and dry it in a drying oven at 80℃.

[0063] (2) Copper tube surface pretreatment: Then put the copper tube into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., put the copper tube to be degreased into it, boil for 15 minutes, or vibrate with ultrasonic waves for 30 minutes, rinse with deionized water to remove surface oil, and then put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is: according to the ratio, 1000ml of deionized water, 120g of chromium anhydride, and 30ml of sulfuric acid, at a temperature of 75℃ for 5 minutes. After acid pickling, the steel core is immediately put into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass, and the neutralization time is 3 minutes. After neutralization, rinse with deionized water and dry in a drying oven at 80℃.

[0064] 3. Solder processing

[0065] (1) Cleaning of solder wire: Place Ø1mm solder wire Cu595 / BCu84NiMn (Mn11-13 / Ni2-4 / Cu BAL) into an acetone bath, ultrasonically vibrate and clean for 30 minutes, rinse twice with deionized water, dehydrate with anhydrous ethanol, and then dry in an enamel tray lined with degreased gauze in an 80℃ electric drying oven for later use. If there is rust on the surface of the solder, soak it in a 10% nitric acid solution at 60℃ for 3~5 minutes, and then repeat the above cleaning process.

[0066] (2) Preparation of solder paste: Mix solder powder (with the same material as the solder wire mentioned above, and the same applies to Examples 2-4) with nitrocellulose solution at a mass ratio of 4:1, and stir evenly with a glass rod until no more lumps appear.

[0067] 4. Pre-assembly processing, refer to the attached document. Figure 1 , 5 -8:

[0068] (1) Place the center positioning sleeve on the lower top rod 10 and pass it upward through the center hole of the movable base 2. Then support the graphite tray 14 on the movable base 2. Specifically, the graphite tray 14 is placed outside the center positioning sleeve and its circumference is clamped by the lower V-shaped block 9. Then remove the center positioning sleeve.

[0069] (2) Support the copper tube P2 on the graphite tray 14, and insert the annular boss 14a of the graphite tray 14 into the copper tube P2, which is clamped by the upper V-shaped block in the circumferential direction.

[0070] (3) Start the press-fitting drive unit 11, drive the lower push rod 10 upward through the copper tube P2, and then manually put the lower positioning block 16 onto the expansion joint 17 (the expansion joint 17 is inserted into the positioning hole at the bottom of the lower positioning block 16 and its expansion block 18 is held against the lower positioning block by the action of the spring 20). Then place the steel core P1 on the lower positioning block 16, and insert the lower positioning protrusion 16a of the lower positioning block 16 into the lower positioning hole P1b of the steel core P1. Finally, start the upper disengagement drive unit 12, press the upper positioning block 15 down separately until its upper positioning protrusion 15a is inserted into the upper positioning hole P1a of the steel core P1, so as to realize the vertical press-fitting and fixing of the steel core P1.

[0071] 5. Application of solder paste and winding of solder wire: Apply the paste P4 evenly to the entire outer surface of the steel core to form a solder paste layer. Then, wind the Ø1mm solder wire around the end of the steel core (i.e., the wire coil P3 in the figure. The wire coil P3 can be placed on the upper end of the steel core P1 before pre-assembly processing). The amount and shape of the wire coil P3 should be sufficient to fill the area between the stainless steel core and the conical opening P1c of the copper tube.

[0072] 6. The assembly of the steel core and copper tube is carried out by using a steel core pressing device to press the steel core into the copper tube. Specifically, the pressing drive unit drives the lower pressing assembly, the upper pressing assembly and the steel core to move down together until the steel core is fully inserted into the copper tube.

[0073] 7. Vacuum sintering: The composite steel core-copper tube is placed in a vacuum sintering furnace for vacuum sintering to obtain a copper-clad steel product. The vacuum sintering conditions are as follows:

[0074] The room temperature is raised to 450℃ and maintained for 45 minutes; the temperature is held at 450℃ for 30 minutes; the temperature is raised from 450℃ to 700℃ and maintained for 1 hour; the temperature is raised from 700℃ to 850℃ and maintained for 50 minutes; the temperature is held at 850℃ for 40 minutes; the temperature is raised from 850℃ to 900℃ and maintained for 30 minutes; the temperature is raised to 900℃ and maintained for 45 minutes before power is cut off; the temperature is lowered to 450℃ and then rapidly cooled with nitrogen; the temperature is lowered to ≤40℃ before the product is removed from the furnace to obtain copper-clad steel.

[0075] 8. After the copper-clad steel products are removed from the furnace, they are sanded, turned, drilled, and tapped on a lathe to finally process them into the required shape. The turning process includes removing the vertical height area where the tapered opening is located (i.e., Figure 1 The area above the dashed line L1) and the vertical height area where the lower positioning hole and the annular boss are located (i.e. Figure 1 (The area below the dashed line L2).

[0076] Testing revealed that the copper-clad steel product prepared in this embodiment exhibited a bonding strength of 125 N / mm² between the copper layer and the steel core. (The bonding strength test was conducted on a 1 cm thick section of the finished copper-clad steel product, excluding the end areas. The tested sample is shown in the image.) Figure 2 As shown, the metallographic diagram of the copper-steel cross-section of the product is also shown below. Figure 3 As shown in the photo, the copper and steel end face of the product is as follows: Figure 4 As shown in the figure, the conductivity is 58.1 MS / m, and the leakage rate is <1.8*10. -8 pa.m 3 / s.

[0077] Among them, the steel core P1 pressing device in step 6 above includes a fixed base 1, an upper pressing assembly, a movable base 2 and a lower pressing assembly arranged from top to bottom above the fixed base 1, and a pressing drive unit 11 for the upper pressing assembly and the lower pressing assembly to move vertically.

[0078] The fixed base 1 has a vertical guide on each side, which is a column 3. The upper surface of the fixed base 1 has a central through hole and several clamping blocks distributed around the central through hole. The clamping blocks are V-shaped, including a first V-shaped clamping block and a second V-shaped clamping block. A pair of first V-shaped clamping blocks are used to clamp and fix the graphite tray 14, and a pair of second V-shaped clamping blocks are used to clamp and fix the copper tube P2. The first V-shaped clamping block and the second V-shaped clamping block are used for partitioned clamping to ensure the stability of the graphite tray 14 and the copper tube P2 during the pressing process. The movable base 2 can be provided with a cross-shaped sliding groove 2a. The first V-shaped clamping block and the second V-shaped clamping block can move along the sliding groove 2a to adapt to copper tubes P2 of different sizes.

[0079] The upper pressing assembly includes an upper positioning block 15, an upper bearing plate, and an upper disengagement drive unit 12. The upper bearing plate includes a first upper bearing plate 4 and a second upper bearing plate 5 arranged in parallel from bottom to top. The two sides of the first upper bearing plate 4 and the second upper bearing plate 5 are respectively slidably sleeved on the column 3. The upper positioning block 15 is installed on the lower part of the first upper bearing plate 4. The upper disengagement drive unit 12 is installed on the lower part of the second upper bearing plate 5 and its output end is connected to the first upper bearing plate 4.

[0080] The lower pressing assembly includes a lower positioning block 16, a lower push rod 10, a lower bearing plate, and a lower disengagement drive unit 13. The lower positioning block 16 is disposed in the graphite tray 14 and is inserted into the lower push rod 10. The lower bearing plate includes a first lower bearing plate 6 and a second lower bearing plate 7 arranged parallel from top to bottom. The two sides of the first lower bearing plate 6 and the second lower bearing plate 7 are respectively slidably sleeved on the column 3. The two sides of the second upper bearing plate 5 and the second lower bearing plate 7 are also fixedly connected by a synchronizing rod 8 (the synchronizing rod 8 is arranged parallel to the outside of the column 3). The two sides of the first upper bearing plate 4 and the first lower bearing plate 6 are slidably sleeved on the column 3 and the synchronizing rod 8. The lower push rod 10 is installed on the upper part of the first lower bearing plate 6. The lower disengagement drive unit 13 is installed on the lower part of the second lower bearing plate 7 and its output end is connected to the first lower bearing plate 6.

[0081] The steel core P1 has an upper positioning hole P1a and a lower positioning hole P1b at its two axial ends respectively. The lower end of the upper positioning block 15 has an upper positioning protrusion 15a that cooperates with the upper positioning hole P1a. The upper end of the lower positioning block has a lower positioning protrusion 16a that cooperates with the lower positioning hole P1b.

[0082] The graphite tray 14 has an annular protrusion 14a protruding upward on its upper surface. The annular protrusion 14a has a downward through step hole 14b on its inner side. The lower push rod 10 can pass through the step hole 14b from bottom to top. The lower positioning block 16 can be completely housed in the step hole 14b.

[0083] The upper end of the lower push rod 10 is coaxially mounted with an expansion joint 17, and the side of the expansion joint 17 is elastically connected with several expansion blocks 18. Specifically, the side of the expansion joint 17 is provided with several guide grooves 17a, and the expansion blocks 18 are slidably disposed in the guide grooves 17a. A pair of guide bolts 19 distributed from top to bottom pass through the expansion blocks 18 and are threadedly connected to the side wall of the guide grooves 17a. A spring 20 is sleeved on the guide bolts 19, and the two ends of the spring 20 abut against the expansion blocks 18 and the side wall of the guide grooves 17a, respectively.

[0084] The press-fitting drive unit 11 is mounted on the fixed base 1 and its output end is connected to the lower support plate.

[0085] Among them, the press-fit drive unit 11 is preferably an electric cylinder with controllable stroke, and the upper release drive unit 12 and the lower release drive unit 13 can be pneumatic cylinders, hydraulic cylinders or electric cylinders.

[0086] Before pressing, the expansion joint 17, through its circumferential expansion block 18, is in the positioning hole at the bottom of the lower positioning block 16, which can effectively prevent the lower positioning block 16 from shaking and ensure reliable centering. At the same time, it can facilitate the subsequent disengagement of the lower positioning block 16 and the lower positioning rod.

[0087] After the pressing is completed, the upper disengagement drive unit 12 drives the upper positioning block 15 to move upward, and the lower disengagement drive unit 13 drives the lower push rod 10 and the lower positioning block 16 to move downward. When the lower positioning block 16 is blocked by the step surface of the step through hole 14b, it remains in the step through hole 14b. The expansion joint 17 disengages from the lower positioning block 16 and continues to move downward with the lower push rod 10 until it is completely disengaged from the graphite tray 14 vertically.

[0088] Example 2

[0089] 1. Raw material preparation:

[0090] Steel core: 304 stainless steel, outer diameter Ø46 0 / -0.10 The long tube has an inner diameter of Ø24 and a length of 560±0.2mm. The outer surface of the long tube is roughened with a steel brush, and its roughness is Ra12.5. The end face of the stainless steel rod is free of burrs.

[0091] Copper tubing: 99.95% pure oxygen-free copper; outer diameter Ø78mm, inner diameter Ø46mm. +0.1 / +0.05 The upper end of the tube has a tapered opening with a depth of 20mm and a chamfer angle of 30 degrees, and the length of the copper tube is 560±0.2mm.

[0092] 2. Surface pretreatment of steel core and copper tube

[0093] (1) Surface pretreatment of steel core: Remove oxide scale, oil stains and other impurities from the surface of the steel core. Then, put the steel core into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., and boil it for 15 minutes or vibrate it with ultrasound for 30 minutes. Rinse it with deionized water to remove surface oil stains. Then, put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is as follows (by mass percentage): hydrofluoric acid: 10%, nitric acid: 25%, water: balance. The acid pickling temperature is 70℃, and the soaking time is 15 minutes to further remove surface impurities, improve the wettability of the steel core surface to the solder, and enhance the bonding force between the subsequent copper layer and the steel core. After acid pickling, put the steel core into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution (by mass percentage). The neutralization time is 3 minutes. After neutralization, rinse it with deionized water and dry it in a drying oven at 80℃.

[0094] (2) Copper tube surface pretreatment: Then put the copper tube into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., put the copper tube to be degreased into it, boil for 15 minutes, or vibrate with ultrasonic waves for 30 minutes, rinse with deionized water to remove surface oil, and then put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is: according to the ratio, 1000ml of deionized water, 120g of chromium anhydride, and 30ml of sulfuric acid, at a temperature of 75℃ for 5 minutes. After acid pickling, the steel core is immediately put into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass, and the neutralization time is 3 minutes. After neutralization, rinse with deionized water and dry in a drying oven at 80℃.

[0095] 3. Solder processing

[0096] (1) Cleaning of solder wire: Place Ø1mm solder wire Cu595 / BCu84NiMn (Mn11-13 / Ni2-4 / Cu BAL) into an acetone bath, ultrasonically vibrate and clean for 30 minutes, rinse twice with deionized water, dehydrate with anhydrous ethanol, and then dry in an electric drying oven at 80~100℃ in an enamel tray lined with degreased gauze. If there is rust on the surface of the solder, soak it in a 10% nitric acid solution at 50~60℃ for 3~5 minutes, and then repeat the above cleaning process.

[0097] (2) Preparation of solder paste: Mix solder powder and nitrocellulose solution at a mass ratio of 4:1, stir evenly with a glass rod until no more lumps appear.

[0098] 4. Pre-assembly processing, refer to the attached document. Figure 1 , 4 -7:

[0099] (1) Place the center positioning sleeve on the lower top rod and pass it upward through the center hole of the movable base. Then support the graphite tray on the movable base. Specifically, the graphite tray is placed outside the center positioning sleeve and its circumference is clamped by the lower V-shaped block. Then remove the center positioning sleeve.

[0100] (2) The copper tube is supported on the graphite tray, and the annular boss of the graphite tray is inserted into the copper tube, and its circumference is clamped by the upper V-shaped block.

[0101] (3) Start the press-fitting drive unit, drive the lower push rod upward through the copper tube, and then manually put the lower positioning block on the expansion joint (the expansion joint is inserted into the positioning hole at the bottom of the lower positioning block and its expansion block is pressed against the lower positioning block by the spring). Then place the steel core on the lower positioning block, and insert the lower positioning protrusion of the lower positioning block into the lower positioning hole of the steel core. Finally, start the upper disengagement drive unit, press the upper positioning block down separately until its upper positioning protrusion is inserted into the upper positioning hole of the steel core, so as to realize the vertical press-fitting and fixing of the steel core.

[0102] 5. Applying solder paste and winding solder wire: Apply the paste evenly to the entire outer surface of the steel core, and then wind Ø1mm solder wire around the end of the steel core. The amount and shape of the solder wire coil should be enough to fill the area between the stainless steel core and the conical opening of the copper tube.

[0103] 6. The assembly of the steel core and copper tube is carried out by using a steel core pressing device to press the steel core into the copper tube. Specifically, the pressing drive unit drives the lower pressing assembly, the upper pressing assembly and the steel core to move down together until the steel core is fully inserted into the copper tube.

[0104] 7. Vacuum sintering: The composite steel core-copper tube is placed in a vacuum sintering furnace for vacuum sintering to obtain a copper-clad steel product. The vacuum sintering conditions are as follows:

[0105] The room temperature is raised to 450℃ and maintained for 45 minutes; then held at 450℃ for 30 minutes; the temperature is raised from 450℃ to 700℃ and maintained for 1 hour; the temperature is raised from 700℃ to 850℃ and maintained for 50 minutes; then held at 850℃ for 40 minutes; the temperature is raised from 850℃ to 900℃ and maintained for 30 minutes; then held at 900℃ for 45 minutes and the power is turned off; after cooling to 450℃, nitrogen is added and the temperature is rapidly cooled; the temperature is then lowered to ≤40℃ before the furnace is removed from the oven.

[0106] 8. After the copper-clad steel products are removed from the furnace, they are sanded, turned, drilled, and tapped on a lathe to finally process them into the required shape. The turning process includes removing the vertical height area where the tapered opening is located (i.e., Figure 1 The area above the dashed line L1) and the vertical height area where the lower positioning hole and the annular boss are located (i.e. Figure 1 (The area below the dashed line L2).

[0107] Testing revealed that the copper-clad steel product prepared in this embodiment exhibited a bonding strength between the copper layer and the steel core of 153 N / mm², an electrical conductivity of 58 MS / m, and a leakage rate of <1.8*10⁻⁸ Pa·m³ / s.

[0108] Example 3

[0109] 1. Raw material preparation:

[0110] Steel core: 40CrNiMo alloy steel, outer diameter Ø30 0 / -0.10 The long bar is 165±0.2mm in length. The outer surface of the long bar is roughened with a steel brush, and its roughness is Ra12.5. The end face of the stainless steel bar is free of burrs.

[0111] Copper tubing: 99.95% pure oxygen-free copper; outer diameter Ø45mm, inner diameter Ø30mm. +0.1 / +0.05 The upper end of the tube has a tapered opening with a depth of 10mm and a chamfer angle of 30 degrees, and the length of the copper tube is 165±0.2mm.

[0112] 2. Surface pretreatment of steel core and copper tube

[0113] (1) Surface pretreatment of steel core: Remove oxide scale, oil stains and other impurities from the surface of the steel core. Then, put the steel core into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., and boil it for 10 minutes or vibrate it with ultrasound for 20 minutes. Rinse it with deionized water to remove surface oil stains. Then, put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is as follows: 60ml deionized water, 22ml hydrogen peroxide, 18ml oxalic acid. The acid pickling temperature is 50℃ and the soaking time is 30s to further remove surface impurities, improve the wettability of the steel core surface to the solder, and enhance the bonding force between the subsequent copper layer and the steel core. After acid pickling, put the steel core into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass. The neutralization time is 3 minutes. After neutralization, rinse it with deionized water and dry it in a drying oven at 80℃.

[0114] (2) Copper tube surface pretreatment: Then put the copper tube into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., put the copper tube to be degreased into it, boil for 10 minutes, or vibrate with ultrasonic waves for 20 minutes, rinse with deionized water to remove surface oil, and then put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is: according to the ratio, 1000ml of deionized water, 120g of chromium anhydride, and 30ml of sulfuric acid, at a temperature of 75℃ for 5 minutes. After acid pickling, the steel core is immediately put into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass, and the neutralization time is 3 minutes. After neutralization, rinse with deionized water and dry in a drying oven at 80℃.

[0115] 3. Solder processing

[0116] (1) Cleaning of solder wire: Place Ø1mm solder wire Cu595 / BCu84NiMn (Mn11-13 / Ni2-4 / Cu BAL) into an acetone bath, ultrasonically vibrate and clean for 30 minutes, rinse twice with deionized water, dehydrate with anhydrous ethanol, and then dry in an enamel tray lined with degreased gauze in an 80℃ electric drying oven for later use. If there is rust on the surface of the solder, soak it in a 10% nitric acid solution at 60℃ for 3~5 minutes, and then repeat the above cleaning process.

[0117] (2) Preparation of solder paste: Mix solder powder and nitrocellulose solution at a mass ratio of 4:1, stir evenly with a glass rod until no more lumps appear.

[0118] 4. Pre-assembly processing, refer to the attached document. Figure 1 , 4 -7:

[0119] (1) Place the center positioning sleeve on the lower top rod and pass it upward through the center hole of the movable base. Then support the graphite tray on the movable base. Specifically, the graphite tray is placed outside the center positioning sleeve and its circumference is clamped by the lower V-shaped block. Then remove the center positioning sleeve.

[0120] (2) The copper tube is supported on the graphite tray, and the annular boss of the graphite tray is inserted into the copper tube, and its circumference is clamped by the upper V-shaped block.

[0121] (3) Start the press-fitting drive unit, drive the lower push rod upward through the copper tube, and then manually put the lower positioning block on the expansion joint (the expansion joint is inserted into the positioning hole at the bottom of the lower positioning block and its expansion block is pressed against the lower positioning block by the spring). Then place the steel core on the lower positioning block, and insert the lower positioning protrusion of the lower positioning block into the lower positioning hole of the steel core. Finally, start the upper disengagement drive unit, press the upper positioning block down separately until its upper positioning protrusion is inserted into the upper positioning hole of the steel core, so as to realize the vertical press-fitting and fixing of the steel core.

[0122] 5. Applying solder paste and winding solder wire: Apply the paste evenly to the entire outer surface of the steel core, and then wind Ø1mm solder wire around the end of the steel core. The amount and shape of the solder wire coil should be enough to fill the area between the stainless steel core and the conical opening of the copper tube.

[0123] 6. The assembly of the steel core and copper tube is carried out by using a steel core pressing device to press the steel core into the copper tube. Specifically, the pressing drive unit drives the lower pressing assembly, the upper pressing assembly and the steel core to move down together until the steel core is fully inserted into the copper tube.

[0124] 7. Vacuum sintering: The composite steel core-copper tube is placed in a vacuum sintering furnace for vacuum sintering to obtain a copper-clad steel product. The vacuum sintering conditions are as follows:

[0125] The room temperature is raised to 450℃ and maintained for 45 minutes; then held at 450℃ for 30 minutes; the temperature is raised from 450℃ to 700℃ and maintained for 1 hour; the temperature is raised from 700℃ to 850℃ and maintained for 50 minutes; then held at 850℃ for 40 minutes; the temperature is raised from 850℃ to 900℃ and maintained for 30 minutes; then held at 900℃ for 45 minutes and the power is turned off; after cooling to 450℃, nitrogen is added and the temperature is rapidly cooled; the temperature is then lowered to ≤40℃ before the furnace is removed from the oven.

[0126] 8. After the copper-clad steel products are removed from the furnace, they are sanded, turned, drilled, and tapped on a lathe to finally process them into the required shape. The turning process includes removing the vertical height area where the tapered opening is located (i.e., Figure 1 The area above the dashed line L1) and the vertical height area where the lower positioning hole and the annular boss are located (i.e. Figure 1 (The area below the dashed line L2).

[0127] Testing revealed that the copper-clad steel product prepared in this embodiment exhibited a bonding strength between the copper layer and the steel core of 165 N / mm², an electrical conductivity of 58.2 MS / m, and a leakage rate of <1.8*10⁻⁸ Pa·m³ / s.

[0128] Example 4

[0129] 1. Raw material preparation:

[0130] Steel core: 42CrMo alloy steel, outer diameter Ø25 0 / -0.10 The long bar is 125±0.2mm in length. The outer surface of the long bar is roughened with a steel brush, and its roughness is Ra12.5. The end face of the stainless steel bar is free of burrs.

[0131] Copper tubing: 99.95% pure oxygen-free copper; outer diameter Ø45mm, inner diameter Ø25mm. +0.1 / +0.05The upper end of the tube has a tapered opening with a depth of 10mm and a chamfer angle of 30 degrees, and the length of the copper tube is 125±0.2mm.

[0132] 2. Surface pretreatment of steel core and copper tube

[0133] (1) Surface pretreatment of steel core: Remove oxide scale, oil stains and other impurities from the surface of the steel core. Then, put the steel core into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., and boil it for 10 minutes or vibrate it with ultrasound for 20 minutes. Rinse it with deionized water to remove surface oil stains. Then, put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is as follows: 60ml deionized water, 22ml hydrogen peroxide, 18ml oxalic acid. The acid pickling temperature is 50℃ and the soaking time is 30s to further remove surface impurities, improve the wettability of the steel core surface to the solder, and enhance the bonding force between the subsequent copper layer and the steel core. After acid pickling, put the steel core into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass. The neutralization time is 3 minutes. After neutralization, rinse it with deionized water and dry it in a drying oven at 80℃.

[0134] (2) Copper tube surface pretreatment: Then put the copper tube into a synthetic cleaning agent, such as Jinliang Neutral Detergent JL-317 from Guangzhou Jingliang Technology Co., Ltd., put the copper tube to be degreased into it, boil for 10 minutes, or vibrate with ultrasonic waves for 20 minutes, rinse with deionized water to remove surface oil, and then put it into an acid pickling tank for acid pickling treatment. The acid pickling solution formula is: according to the ratio, 1000ml of deionized water, 120g of chromium anhydride, and 30ml of sulfuric acid, at a temperature of 75℃, and an acid pickling time of 3~5 minutes. After acid pickling, the steel core is immediately put into a neutralization tank for neutralization treatment. The neutralization solution is a 5% ammonia solution by mass, and the neutralization time is 3 minutes. After neutralization, rinse with deionized water and dry in a drying oven at 80℃.

[0135] 3. Solder processing

[0136] (1) Cleaning of solder wire: Place Ø1mm solder wire Cu595 / BCu84NiMn (Mn11-13 / Ni2-4 / Cu BAL) into an acetone bath, ultrasonically vibrate and clean for 30 minutes, rinse twice with deionized water, dehydrate with anhydrous ethanol, and then dry in an electric drying oven at 80~100℃ in an enamel tray lined with degreased gauze. If there is rust on the surface of the solder, soak it in a 10% nitric acid solution at 50~60℃ for 3~5 minutes, and then repeat the above cleaning process.

[0137] (2) Preparation of solder paste: Mix solder powder and nitrocellulose solution at a mass ratio of 4:1, stir evenly with a glass rod until no more lumps appear.

[0138] 4. Pre-assembly processing, refer to the attached document. Figure 1 , 4 -7:

[0139] (1) Place the center positioning sleeve on the lower top rod and pass it upward through the center hole of the movable base. Then support the graphite tray on the movable base. Specifically, the graphite tray is placed outside the center positioning sleeve and its circumference is clamped by the lower V-shaped block. Then remove the center positioning sleeve.

[0140] (2) The copper tube is supported on the graphite tray, and the annular boss of the graphite tray is inserted into the copper tube, and its circumference is clamped by the upper V-shaped block.

[0141] (3) Start the press-fitting drive unit, drive the lower push rod upward through the copper tube, and then manually put the lower positioning block on the expansion joint (the expansion joint is inserted into the positioning hole at the bottom of the lower positioning block and its expansion block is pressed against the lower positioning block by the spring). Then place the steel core on the lower positioning block, and insert the lower positioning protrusion of the lower positioning block into the lower positioning hole of the steel core. Finally, start the upper disengagement drive unit, press the upper positioning block down separately until its upper positioning protrusion is inserted into the upper positioning hole of the steel core, so as to realize the vertical press-fitting and fixing of the steel core.

[0142] 5. Applying solder paste and winding solder wire: Apply the paste evenly to the entire outer surface of the steel core, and then wind Ø1mm solder wire around the end of the steel core. The amount and shape of the solder wire coil should be enough to fill the area between the stainless steel core and the conical opening of the copper tube.

[0143] 6. The assembly of the steel core and copper tube is carried out by using a steel core pressing device to press the steel core into the copper tube. Specifically, the pressing drive unit drives the lower pressing assembly, the upper pressing assembly and the steel core to move down together until the steel core is fully inserted into the copper tube.

[0144] 7. Vacuum sintering: The composite steel core-copper tube is placed in a vacuum sintering furnace for vacuum sintering to obtain a copper-clad steel product. The vacuum sintering conditions are as follows:

[0145] The room temperature is raised to 450℃ and maintained for 45 minutes; then held at 450℃ for 30 minutes; the temperature is raised from 450℃ to 700℃ and maintained for 1 hour; the temperature is raised from 700℃ to 850℃ and maintained for 50 minutes; then held at 850℃ for 40 minutes; the temperature is raised from 850℃ to 900℃ and maintained for 30 minutes; then held at 900℃ for 45 minutes and the power is turned off; after cooling to 450℃, nitrogen is added and the temperature is rapidly cooled; the temperature is then lowered to ≤40℃ before the furnace is removed from the oven.

[0146] 8. After the copper-clad steel products are removed from the furnace, they are sanded, turned, drilled, and tapped on a lathe to finally process them into the required shape. The turning process includes removing the vertical height area where the tapered opening is located (i.e., Figure 1 The area above the dashed line L1) and the vertical height area where the lower positioning hole and the annular boss are located (i.e. Figure 1 (The area below the dashed line L2).

[0147] Testing showed that the copper-clad steel product prepared in this embodiment had a bonding strength between the copper layer and the steel core of 175 N / mm², and an electrical conductivity of 58.2 MS / m. The leakage rate was <1.8*10⁻⁸ Pa·m³ / s.

[0148] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0149] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation process of a copper-clad steel product, comprising the following steps: S1, surface pretreatment of the steel core and the copper tube, cleaning the steel core and the copper tube respectively to remove surface impurities; S2, treatment of the solder, mixing and stirring the solder powder and the nitrocellulose solution according to a mass ratio of 4:1 to obtain a solder paste; S3, application of the solder paste and winding of the solder wire, uniformly applying the solder paste on the entire side wall of the steel core, and winding the solder wire at the upper end of the steel core; S4, assembly of the steel core and the copper tube, inserting the steel core with the applied solder paste and solder wire into the copper tube, and placing the solder wire in the tapered opening at the upper end of the lumen of the copper tube; S5, vacuum sintering, placing the combined steel core-copper tube as a whole in a vacuum sintering furnace for vacuum sintering to obtain a copper-clad steel product.

2. A process for the production of a copper clad steel product as claimed in claim 1, characterized in that: The steel core is made of 304 stainless steel, alloy steel 40CrNiMo or alloy steel 42CrMo; The copper tube is made of oxygen-free copper with a purity of not less than 99.9%.

3. A process for the production of a copper clad steel product as claimed in claim 1, wherein: The cleaning of the steel core comprises the following steps: degreasing cleaning, cleaning the steel core to be washed through a detergent solution; acid cleaning, cleaning the steel core after degreasing treatment through an acidic solution; neutralization treatment, cleaning the steel core after acid cleaning with a neutralizing solution, rinsing clean with deionized water after neutralization, and drying for standby use.

4. A process for the production of a copper clad steel product as claimed in claim 3, wherein: If the steel core is made of 304 stainless steel, the raw materials of the pickling solution are hydrofluoric acid 8%~10%, nitric acid 25%~28%, and the balance is water, by mass percentage; the pickling conditions are as follows: temperature 70~74℃, soaking cleaning for 10~15 minutes; If the steel core is made of alloy steel 40CrNiMo or alloy steel 42CrMo, the raw materials of the pickling solution are water 60 parts, hydrogen peroxide 20~25 parts, and oxalic acid 15~20 parts, by volume fraction; The raw materials of the pickling solution for the copper tube are water 1000ml, chromic anhydride 120g, and sulfuric acid 30ml, by proportion; the pickling conditions are as follows: temperature 70~80℃, pickling time 3~5 minutes; The neutralizing solution for the steel core and the copper tube is all 2~5% ammonia water solution by mass percentage, and the soaking neutralization time is 1-3 minutes.

5. A process for the production of a copper clad steel product as claimed in claim 1, wherein: The conditions of the vacuum sintering are as follows: room temperature to 450℃, heating for 45min; 450℃ for 30min; 450℃ to 700℃, heating for 1h; 700℃ to 850℃, heating for 50min; 850℃ for 40min; 850℃ to 900℃, heating for 30min; 900℃ for 45min, power off; nitrogen charging after decreasing to 450℃, fast cooling; decreasing to ≤40℃, discharging.

6. A process for the production of a copper clad steel product as claimed in claim 1, wherein: The assembly of the steel core and the copper tube uses a steel core press-fitting device to press-fit the vertical steel core into the copper tube.

7. A process for the production of a copper clad steel product as claimed in claim 6, wherein: The steel core press-fitting device comprises a fixed base, an upper press-fitting assembly arranged above the fixed base from top to bottom, a movable base and a lower press-fitting assembly, and a press-fitting driving unit for vertical movement of the upper press-fitting assembly and the lower press-fitting assembly; The fixed base is provided with vertical guide members on both sides, and the upper end surface of the fixed base is provided with a central through hole and a plurality of clamping blocks distributed around the central through hole. The upper pressing assembly comprises an upper positioning pressing block, an upper bearing plate and an upper disengaging driving unit, the upper positioning pressing block is connected to the output end of the upper disengaging driving unit, the upper disengaging driving unit is installed on the upper bearing plate, and the upper bearing plate is slidably supported on the guide on both sides. The lower pressing assembly comprises a lower positioning pressing block, a lower ejector rod, a lower bearing plate and a lower disengaging driving unit, the lower positioning pressing block is arranged in the graphite tray and is in plug-in cooperation with the lower ejector rod, the lower ejector rod is connected to the output end of the lower disengaging driving unit, the lower disengaging driving unit is installed on the lower bearing plate, the lower bearing plate is slidably supported on the guide on both sides, and the lower bearing plate and the upper bearing plate are connected through a synchronous rod on both sides. The upper positioning pressing block is provided with an upper positioning protrusion on the lower end surface in a downward direction, the upper positioning protrusion is matched with the upper positioning hole, the lower positioning block is provided with a lower positioning protrusion on the upper end surface in an upward direction, and the lower positioning protrusion is matched with the lower positioning hole. The upper surface of the graphite tray is provided with an annular boss in an upward direction, the inner side of the annular boss is provided with a step through hole penetrating downward, the lower ejector rod can pass through the step through hole from bottom to top, and the lower positioning pressing block can be accommodated in the step through hole as a whole. The pressing driving unit is installed on the fixed base and the output end thereof is connected to the lower bearing plate.

8. A process for the production of a copper clad steel product as claimed in claim 7, characterized in that: The upper end of the lower ejector rod is coaxially installed with an expansion joint, and the side surface of the expansion joint is elastically connected with a plurality of expansion blocks. The side surface of the expansion joint is provided with a plurality of guide grooves, the expansion blocks are slidably arranged in the guide grooves, a pair of guide bolts distributed from top to bottom penetrate the expansion blocks and are threadedly connected with the side walls of the guide grooves, springs are sleeved on the guide bolts, and the two ends of the springs abut against the expansion blocks and the side walls of the guide grooves respectively.

9. A process for the production of a copper clad steel product as claimed in claim 8, characterized in that: The assembly process of the steel core and the copper pipe is as follows: S1', the center positioning sleeve is sleeved on the lower ejector rod and passes through the center through hole of the movable base in an upward direction, then the graphite tray is supported on the movable base, specifically, the graphite tray is sleeved outside the center positioning sleeve and is clamped by the lower V-shaped blocks in a circumferential direction, and then the center positioning sleeve is removed; S2', the copper pipe is supported on the graphite tray, the annular boss of the graphite tray is inserted into the copper pipe, and the copper pipe is clamped by the upper V-shaped blocks in a circumferential direction; S3', the pressing driving unit is started to drive the lower ejector rod to pass through the copper pipe in an upward direction, then the lower positioning pressing block is sleeved on the expansion joint (the expansion joint is inserted into the positioning hole at the bottom of the lower positioning pressing block, and the expansion blocks of the expansion joint abut against the lower positioning block under the action of the springs), then the steel core is placed on the lower positioning pressing block, the lower positioning protrusion of the lower positioning pressing block is inserted into the lower positioning hole of the steel core, finally, the upper disengaging driving unit is started to separately press the upper positioning pressing block downward to insert the upper positioning protrusion of the upper positioning pressing block into the upper positioning hole of the steel core, so as to realize the vertical pressing and fixing of the steel core; S4', the pressing driving unit drives the lower pressing assembly, the upper pressing assembly and the steel core to move downward together until the steel core is completely inserted into the copper pipe.

10. A conductive rod for a vacuum interrupter, characterized by, The conductive rod is prepared by the method of any one of claims 1-9.

Images