Extrusion tooling and preparation method of super-wide U-shaped copper bar

Abstract

The application discloses an extrusion tool and a preparation method of an ultra-wide U-shaped copper bar, and belongs to the technical field of copper bars. The extrusion tool comprises a cavity rear cover, a containing cavity and a rear cover hole which are connected in communication in the cavity rear cover; an extrusion die which is arranged in the containing cavity and whose outer periphery is covered by the periphery of the containing cavity, and the extrusion die has a die hole in it; and a flow guide gasket, at least part of which is arranged in the containing cavity and the periphery of at least part of the flow guide gasket is covered by the periphery of the containing cavity, the flow guide gasket abuts against the extrusion die along a first direction so that the extrusion die abuts against the cavity rear cover, and the flow guide gasket has a flow guide hole in it; wherein the flow guide hole, the die hole and the rear cover hole are sequentially connected in communication along the first direction; and the center axis of the die hole is parallel to the center axis of the extrusion die along the first direction. The copper bar prepared by the application has good flatness and smooth surface.

Description

Technical Field

[0001] This invention relates to the technical field of copper processing, and in particular to an extrusion fixture and preparation method for an ultra-wide U-shaped copper busbar. Background Technology

[0002] With the continuous advancement of industrial technology, more and more new types of equipment are emerging, and consequently, the corresponding components are constantly being updated and iterated. Current equipment for producing sputtering targets includes a slider guide channel, which requires both electrical conductivity and sliding guidance capabilities. Therefore, it demands extremely high dimensional accuracy, flatness, and corrosion resistance. This guide channel is U-shaped, and compared to conventional copper busbar products, its structure is more complex and its specifications are larger, with a width of 180mm and a thickness of 40.5mm. The large size and extra-wide dimensions make it more difficult to control dimensional accuracy, such as flatness.

[0003] Currently, large-size copper busbars are generally manufactured using a horizontal extrusion process. Electrolytic plates are smelted and horizontally cast into ingot billets. The ingots are then heated in a furnace, followed by horizontal extrusion, pickling, cleaning, drawing, inspection, and packaging. Products manufactured using this method have a bright surface and good dimensions, but the process is complex, the route is long, and the product yield is low. Furthermore, the extrusion process only involves extrusion pressure, making it difficult to control the straightness of the product exit. Such defects are fatal for copper products used in slide guide channels. Summary of the Invention

[0004] To address the aforementioned problems in existing copper busbar fabrication methods, this paper aims to provide an extrusion fixture and fabrication method for ultra-wide U-shaped copper busbars, resulting in copper busbars with good straightness and smooth surface.

[0005] The specific technical solution is as follows:

[0006] An extrusion fixture for an ultra-wide U-shaped copper busbar includes:

[0007] A cavity rear cover, wherein the cavity rear cover has a communicating receiving cavity and a rear cover hole;

[0008] An extrusion die is disposed within the receiving cavity, and the periphery of the receiving cavity covers the outer periphery of the extrusion die. The extrusion die has a die hole inside.

[0009] A flow guide pad, at least a portion of which is disposed within the receiving cavity, and the periphery of the receiving cavity covers at least a portion of the periphery of the flow guide pad. The flow guide pad presses against the extrusion mold in a first direction so that the extrusion mold abuts against the rear cover of the cavity. The flow guide pad has flow guide holes.

[0010] The flow guide hole, the mold hole, and the rear cover hole are connected sequentially along the first direction;

[0011] The central axis of the die hole is parallel to the central axis of the extrusion die along the first direction.

[0012] The extrusion fixture for the aforementioned ultra-wide U-shaped copper busbar has a U-shaped cross-section for the guide hole, the die hole, and the rear cover hole.

[0013] The above-mentioned extrusion fixture for ultra-wide U-shaped copper busbars includes a die hole and a sizing hole that are interconnected along the first direction. The guide hole, the tapered hole, the sizing hole and the rear cover hole are connected sequentially along the first direction. The depth l of the sizing hole is 1 / 6 to 1 / 4 of the total depth L of the die hole.

[0014] The above-mentioned extrusion fixture for ultra-wide U-shaped copper busbars includes a conical hole comprising: a bottom conical hole of the die and side conical holes of the die at both ends, the two side conical holes of the die being located on one side of the bottom conical hole of the die, and the central axis of the extrusion die being located on the other side of the bottom conical hole of the die.

[0015] In the above-mentioned extrusion fixture for ultra-wide U-shaped copper busbars, the taper α of the bottom conical hole of the die is 5° to 8°, and the taper β of the side conical hole of the die is 10° to 20°.

[0016] The aforementioned extrusion fixture for ultra-wide U-shaped copper busbars includes a guide hole comprising: a guide center hole and guide side holes at both ends thereof, wherein the cross-sectional area of ​​the guide side holes is 4.5-5.5 times the cross-sectional area of ​​the guide center hole.

[0017] The above-mentioned extrusion fixture for ultra-wide U-shaped copper busbars includes a flow guide pad comprising: a back pad, side pads disposed on both sides of the back pad, and a middle pad disposed between the two side pads, wherein the flow guide hole is formed between the back pad, the two side pads and the middle pad.

[0018] A method for preparing an ultra-wide U-shaped copper busbar, wherein the extrusion fixture for the ultra-wide U-shaped copper busbar described in any one of the above-mentioned methods is used, and the preparation method includes:

[0019] Step S1: Smelting: Select single-layer electrolytic plates with a copper content of 99.98wt% or higher as raw materials. Before adding them to the furnace, the electrolytic plates need to be hoisted 20-30cm above the furnace opening and baked for 1-3 minutes. After baking and heating, they can be added to the furnace.

[0020] Step S2: Upward continuous casting: The diameter of the traction copper rod is 23-24.2mm, the traction speed is 300-400mm / min, the pitch is 3-3.5mm, the traction frequency is 105-115 times / min, and the reverse thrust is 0.1-0.2mm / time;

[0021] Step S3: Continuous extrusion: The continuous extruder uses an upper copper rod with a diameter of 23-24.2mm as the extrusion material and also as the guide rod. The total length of the guide rod must be more than 1.8m. The baking temperature is 650-700℃, the baking time of the guide rod is 15-20min, the rotation speed is 3.5-4rpm, and the extrusion current is 600-700A.

[0022] Step S4: Pulling: Maintain the pulling speed at 5-10 m / min.

[0023] In the above-mentioned method for preparing ultra-wide U-shaped copper busbars, in step S4: a drawing fixture is used during the drawing process, the drawing fixture including: a bridge mold and a finished product mold, the bridge mold and the finished product mold having a distance of 1.5-2m.

[0024] The above-mentioned method for preparing ultra-wide U-shaped copper busbars further includes:

[0025] Step S5: Inspection: Inspect the final product for dimensional accuracy, hardness, tensile strength, elongation, density, straightness, and flatness;

[0026] Step S6: Packaging and warehousing.

[0027] The positive effects of the above technical solution compared with the existing technology are:

[0028] This invention achieves the flatness and parallelism of the product to meet the requirements for use of copper busbars for ultra-wide U-shaped slider guide grooves through the design of extrusion and drawing tooling;

[0029] This invention uses a continuous extrusion method to prepare large-size, ultra-wide copper busbars. The process is short, reduces processing steps such as pickling, and produces products with good straightness and high yield. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the overall structure of an extrusion fixture for an ultra-wide U-shaped copper busbar according to the present invention;

[0031] Figure 2 This is a schematic diagram of the overall structure of an extrusion fixture for an ultra-wide U-shaped copper busbar according to the present invention;

[0032] Figure 3 This is a schematic diagram of the flow guide pad of the extrusion tooling for an ultra-wide U-shaped copper busbar according to the present invention;

[0033] Figure 4 This is a schematic diagram of the extrusion die of an extrusion tooling for an ultra-wide U-shaped copper busbar according to the present invention;

[0034] Figure 5 This invention relates to an extrusion fixture for an ultra-wide U-shaped copper busbar. Figure 4Structural cross-sectional view along the AA direction;

[0035] In the attached diagram: 1. Cavity rear cover; 2. Extrusion die; 3. Flow guide gasket; 11. Receiving cavity; 12. Rear cover hole; 21. Die hole; 22. Tapered hole; 23. Sizing hole; 24. Die bottom tapered hole; 25. Die side tapered hole; 31. Flow guide hole; 32. Flow guide center hole; 33. Flow guide side hole; 34. Back pad; 35. Side pad; 36. Center pad. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0037] like Figures 1 to 5 The diagram illustrates a preferred embodiment of an extrusion fixture for an ultra-wide U-shaped copper busbar, comprising: a cavity back cover 1, an extrusion die 2, and a flow guide pad 3. The cavity back cover 1 has a communicating receiving cavity 11 and a back cover hole 12. The extrusion die 2 is disposed within the receiving cavity 11, and the periphery of the receiving cavity 11 covers the outer periphery of the extrusion die 2. The extrusion die 2 has a die hole 21. At least a portion of the flow guide pad 3 is disposed within the receiving cavity 11, and the periphery of the receiving cavity 11 covers at least a portion of the periphery of the flow guide pad 3. The flow guide pad 3 presses against the extrusion die 2 in a first direction so that the extrusion die 2 abuts against the cavity back cover 1. The flow guide pad 3 has a flow guide hole 31.

[0038] Preferably, the main function of the receiving cavity 11 is to withstand deformation. It can be subjected to force through the circumference of the cavity cover to avoid mold deformation and ensure product size and mold life.

[0039] Furthermore, in a preferred embodiment, the flow guide hole 31, the mold hole 21, and the rear cover hole 12 are connected sequentially along the first direction.

[0040] Furthermore, as a preferred embodiment, the central axis of the die hole 21 is parallel to the central axis of the extrusion die 2 along the first direction.

[0041] Furthermore, as a preferred embodiment, the cross-sections of the flow guide hole 31, the mold hole 21, and the rear cover hole 12 are all U-shaped structures.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention.

[0043] In addition to the above, the present invention also has the following embodiments:

[0044] In further embodiments of the present invention, please continue to refer to Figures 1 to 5As shown, the mold hole 21 includes a conical hole 22 and a sizing hole 23 that are interconnected along the first direction. The guide hole 31, the conical hole 22, the sizing hole 23, and the rear cover hole 12 are sequentially connected along the first direction. The depth l of the sizing hole 23 is 1 / 6 to 1 / 4 of the total depth L of the mold hole 21. By controlling the depth of the sizing hole 23, the process resistance is reduced, making molding more convenient.

[0045] In a further embodiment of the present invention, the conical hole 22 includes: a mold bottom conical hole 24 and mold side conical holes 25 at both ends thereon, the two mold side conical holes 25 being located on one side of the mold bottom conical hole 24, and the central axis of the extrusion mold 2 being located on the other side of the mold bottom conical hole 24.

[0046] The distance between the central axis of the die hole 21 and the central axis of the extrusion die 2 along the first direction is 0.5 to 3 mm, which can effectively ensure the filling performance of the bottom material.

[0047] In a further embodiment of the present invention, the taper α of the bottom conical hole 24 of the mold is 5° to 8°, and the taper β of the side conical hole of the mold is 10° to 20°.

[0048] Preferably, the conical hole 22 design increases the intermediate resistance and reduces the edge resistance, ensuring that the extrusion flow rate remains consistent.

[0049] In a further embodiment of the present invention, the guide hole 31 includes: a guide middle hole 32 and guide side holes 33 disposed at both ends thereon, wherein the cross-sectional area of ​​the guide side holes 33 is 4.5-5.5 times the cross-sectional area of ​​the guide middle hole 32.

[0050] In order to control the flow of metal to the sides (normally the flow velocity in the middle is greater than that on both sides), and to ensure that the flow velocity of metal is consistent in all positions of the cavity.

[0051] Meanwhile, the flow guide gasket is designed in three separate parts, which can improve its service life. Because the upper middle part of the gasket is subjected to greater force, it is easy to deform during the extrusion and impact process, and is a vulnerable part. The separate design can effectively reduce costs.

[0052] In a further embodiment of the present invention, the flow guide pad 3 includes: a back pad 34, side pads 35 disposed on both sides of the back pad 34, and a middle pad 36 disposed between the side pads 35, wherein a flow guide hole 31 is formed between the back pad 34, the side pads 35 and the middle pad 36.

[0053] The gasket has a concave internal shape designed to fit the product. This shape is primarily based on the characteristics of metal flow, minimizing the velocity difference between the center and the edges. The detachable design of the flow guide gasket allows for easier replacement of tooling in deformed areas after stress.

[0054] Preparation methods include:

[0055] Step S1: Smelting: Select single-layer electrolytic plates with a copper content of 99.98wt% or higher as raw materials. Before adding them to the furnace, the electrolytic plates need to be hoisted 20-30cm above the furnace opening and baked for 1-3 minutes until there are no water marks on the electrolytic plates. After baking and heating, they can be added to the melting furnace. The temperature of the upper furnace is controlled at 1150-1160℃. The melting furnace is protected with charcoal, with a covering thickness of more than 80mm. The holding furnace is protected with graphite flakes, with a covering thickness of more than 50mm.

[0056] ① Selection of covering agent: Charcoal is used for covering the melting furnace to reduce the copper in order to save costs; graphite flakes are used in the holding furnace mainly because the flakes will not produce slag after burning, thus ensuring the purity of the copper in the melting furnace.

[0057] ②Cover thickness selection: Because charcoal particles are relatively large, they cannot completely isolate the air, so the thickness needs to be increased to ensure that the charcoal on the top of the copper melt is all CO for reduction. Graphite flakes, on the other hand, are thin and do not need to be too thick to achieve the isolation effect. Therefore, the charcoal coverage thickness of the melting furnace is 80mm, and the graphite flake coverage thickness of the holding furnace is 50mm.

[0058] Step S2: Upward continuous casting: The diameter of the traction copper rod is 23-24.2mm, the traction speed is 300-400mm / min, the pitch is 3-3.5mm, the traction frequency is 105-115 times / min, and the reverse thrust is 0.1-0.2mm / time;

[0059] During the condensation process, metals can experience shrinkage cavities (metals expand and contract with temperature changes; liquid metal shrinks in volume during solidification, and copper shrinks by about 4.92% during the condensation process). To address this shrinkage issue at the end of condensation, the production process involves pushing the copper rod back into the molten copper to fill the shrinkage cavity area, ensuring the density and uniformity of the copper rod's structure. The back-pushing amount L1 is controlled at 0.1-0.2 mm per push. If the back-pushing is too short, the shrinkage cavities will not be filled by molten copper, resulting in air pockets inside the copper rod. If the back-pushing is too long, some of the condensed section of the copper rod will re-enter the high-temperature molten copper, causing changes in the copper grains immersed in the molten copper and fluctuations in the copper rod's performance.

[0060] Step S3: Continuous extrusion: The continuous extruder uses an upper copper rod with a diameter of 23-24.2mm as the extrusion material and also as the guide rod. The total length of the guide rod must be more than 1.8m. The baking temperature is 650-700℃, the baking time of the guide rod is 15-20min, the rotation speed is 3.5-4rpm, and the extrusion current is 600-700A.

[0061] Preferably, a continuous extrusion press is used for continuous extrusion. First, the extrusion derrick is used to fill the cavity of the continuous extrusion press. The extrusion derrick needs to be baked to 650-700℃ for 15-20 minutes. The total length of the derrick needs to be controlled to be more than 1.8m. After the hot derrick is filled, a cold copper rod is fed in. The copper rod feed diameter is 23-24.2mm. The extrusion speed is controlled to be below 3.5-4rpm. The internal temperature of the cavity is controlled within the range of 450-650℃.

[0062] ① Copper Rod Diameter Design: The 550 continuous extrusion press uses 23-24.2mm copper rods as feed material. Conventional continuous extrusion copper busbars use φ25mm copper rods. Adjusting the feed copper rod diameter from φ25mm to φ23-24.2mm results in several improvements. Under the same conditions, the extrusion current for φ25mm copper rods is 750-800A. Excessive resistance during metal flow leads to excessive current, causing equipment stalling during continuous extrusion due to insufficient capacity. In contrast, the extrusion current for 23-24.2mm copper rods is only 600-700A, approximately 100A lower than that for 25mm copper rods. This prevents equipment stalling during extrusion and ensures product density. For the same machine model, reducing the copper rod feed diameter results in lower current, less forming resistance, and easier extrusion.

[0063] ② Extrusion speed: The speed should be controlled below 3.5-4 rpm. The faster the extrusion speed, the greater the difference in flow velocity between the surface metal and the middle metal. Simultaneously, the difference in flow velocity between the middle metal and the metal on both sides in the width direction also increases. When the metal flow velocity difference exceeds 30 mm / s, the unevenness of flow increases, resulting in poor product forming effect, uneven product density, and uneven microstructure. To ensure consistent metal flow, a low speed should be selected to control the speed difference. When the speed is below 4 rpm, the difference in metal flowability is basically stable within 5 mm / s. However, at low speeds, the extrusion heat is insufficient, the copper busbar has poor ductility, and there are problems such as incomplete extrusion and poor density. Therefore, the speed is controlled at 3.5-4 rpm.

[0064] ③ Lead rod length and temperature: Before connecting the cold copper rod, it is necessary to ensure that the cavity is completely filled with the hot lead rod. The lead rod length should be controlled above 1.8m, and the baking temperature of the lead rod should be controlled at 650-700℃ (the temperature will drop after the cold rod is removed, and the temperature will also drop when it comes into contact with the cold tooling. The set temperature of the lead rod will be higher than the cavity temperature during normal production).

[0065] The combined effect is to control the metal flow rate, the density of the metal filling, and the dimensional fluctuations of the metal. By designing to increase the metal flow rate in the middle and edge areas, the flow rate difference between different parts is controlled within 5mm / s, which better ensures the density and dimensional stability of the metal. A cavity back cover designed to match the product shape ensures dimensional stability.

[0066] Step S4: Pulling: Maintain the pulling speed at 5-10 m / min;

[0067] The extruded copper busbars are drawn using a drawing machine and drawing fixtures. The drawing speed is controlled at 5-10 m / min, the straightening tension is controlled at 240-270 MPa, and the straightening length is controlled at 40-60 mm (the straightening length refers to the length of time the hydraulic cylinder moves backward after the product is gripped by the jaws).

[0068] ① The drawing speed should be controlled at 5-10 m / min. The speed during the drawing process will have a certain impact on the product size and straightness. When the straightness of the drawing blank is abnormal, it is necessary to control the low speed to ensure that the drawn product is straightened before entering the mold. If the drawing speed is too fast, the product will be pulled out before it can be straightened, and the straightness will not meet the expected requirements.

[0069] ② The improved drawing tooling adopts a bridge die production method. A bridge die smaller than the extruded billet size and a die larger than the finished product die are added 1.5-2 meters in front of the finished product die for pre-adjustment before drawing. It is mainly used to adjust the billet to a straighter state when it is slightly bent, so that the straightness and size can be controlled within the expected range during subsequent drawing.

[0070] ③ The straightening tension should be controlled above the product's yield strength to ensure that the product can undergo plastic deformation. However, it should not be too large, as this could lead to the risk of the product breaking.

[0071] ④ The straightening length is designed to be between 40-60mm. This design primarily considers the elastic rebound of copper. As long as the elastic rebound limit is not exceeded, there will be no plastic deformation, and the product will spring back to its original state after stretching and straightening. If the stretching length is too long, the plastic deformation will be excessive, resulting in significant changes in the transverse cross-sectional dimensions, and potentially even breakage. Testing revealed that when the stretching length is 40-60mm, representing 0.5-0.75% of the total length (8 meters), the dimensional change after stretching remains stable within 0.02mm, achieving a balance between straightness and dimensional accuracy.

[0072] Step S5: Inspection: Inspect the final product for dimensional accuracy, hardness, tensile strength, elongation, density, straightness, and flatness;

[0073] Step S6: Packaging and warehousing.

[0074] In the above-mentioned method for preparing ultra-wide U-shaped copper busbars, in step S4: a drawing fixture is used during the drawing process. The drawing fixture includes a bridge mold and a finished product mold. There is a distance of 1.5-2m between the bridge mold and the finished product mold.

[0075] The chamfers at all locations of the bridging die are 8-12°, and no chamfering difference treatment is required. The length of the sizing zone is controlled at 6-8mm. In addition, the dimensions of the bridging die are 0.5-1.2mm smaller than those of the extrusion die. The deformation at the location of the bridging die is controlled at 5%-12%. The purpose of the design deformation is to better control straightness and dimensional tolerance.

[0076] For the finished mold, the chamfer angle is set to 8-12°, and the sizing strip length is controlled to 6-8mm.

[0077] This invention achieves product flatness and parallelism that meet the requirements for use of copper busbars in ultra-wide U-shaped slider guide grooves through the design of extrusion and drawing fixtures.

[0078] This invention uses a continuous extrusion method to prepare large-size, ultra-wide copper busbars. The process is short, reduces processing steps such as pickling, and produces products with good straightness and high yield.

[0079] Example 1

[0080] This embodiment provides a method for preparing a large-size U-shaped copper busbar with dimensions Y40.5x180mm, including the following steps:

[0081] 1) Smelting: Electrolytic plates with a copper content of 99.98wt% or higher are selected as raw materials and put into the melting furnace for smelting. The smelting and holding temperature is 1155℃. The melting furnace is covered with 90mm thick charcoal and the holding furnace is covered with 60mm thick graphite flakes.

[0082] 2) Upward continuous casting: The diameter of the traction copper rod is 23.5mm, the traction speed is 300mm / min, the traction pitch is controlled at 3mm / time, the reverse thrust is 0.12mm / time, and the traction frequency is controlled at 105 times / min.

[0083] 3) Continuous Extrusion: For tooling, the above-mentioned guide gaskets and cavity back cover are used. Regarding the extrusion die size, a die with a thickness of 41.6mm and a width of 181.5mm is selected. The die sizing band length is 5mm. During continuous extrusion startup, a 23mm diameter upper copper rod is used, with a total rod length of 1.9m. The heating temperature is 650℃, and the baking time is 20 minutes. The extrusion speed is controlled at 3.7rpm during startup, and the extrusion current fluctuates between 620-650A during production. Measurements show that the extruded material thickness is 41.5mm and the width is 181.4mm.

[0084] 4) Drawing: In terms of tooling, a bridge die is used as an intermediate die for production. The thickness of the bridge die is 41.1 mm and the width is 180.9 mm. The drawing speed during the production process is 8 mm / min.

[0085] 5) Inspection: Inspect the final product for dimensional accuracy, hardness, tensile strength, elongation, density, straightness, and flatness.

[0086] 6) Packaging and warehousing: Packaging and warehousing.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the diameter of the upper copper rod is controlled at 25mm, while the other process steps are the same.

[0089] Comparative Example 2

[0090] The difference between this comparative example and Example 1 is that the upward traction speed is 400 mm / min, the traction pitch is 4 mm / time, there is no reverse thrust, the traction frequency is 100 times / min, and the other upward traction process steps are the same.

[0091] Comparative Example 3

[0092] The difference between this comparative example and Example 1 is that the extrusion speed in this example is 4.5 rpm. All other process steps are the same.

[0093] Comparative Example 4

[0094] The difference between this comparative example and Example 1 is that the extrusion tooling in this example does not use a flow guide pad, and the cavity back cover does not use a back cover that matches the target shape; instead, a standard cavity back cover is used. All other process steps are the same.

[0095] Comparative Example 5

[0096] The difference between this comparative example and Example 1 is that the baking temperature of the lead rod is reduced to 15 minutes, but the baking temperature is increased to 700°C, while the other process steps are the same.

[0097] Comparative Example 6

[0098] The difference between this comparative example and Example 1 is that the drawing process does not use a bridge die, but directly uses a drawing die for production, while the other process steps are the same.

[0099] Comparative Example 7

[0100] The difference between this comparative example and Example 1 is that the drawing process uses a bridge die, but the drawing speed is 15m / min, while the other process steps are the same.

[0101] Comparative Example 8

[0102] This embodiment provides a method for preparing a large-size U-shaped copper busbar with dimensions Y40.5x180mm, including the following steps:

[0103] 1) Smelting: Cathode electrolytic plates are selected as raw materials and, after preheating, are put into the upward melting furnace. Charcoal is added to the melting furnace, and graphite flakes are added to the holding furnace. The covering process prevents the molten copper from being exposed to the air.

[0104] 2) Top-draw continuous casting: The diameter of the traction copper rod is 25mm, the traction speed is 450mm / min, the traction pitch is controlled at 4.5mm / time, and the traction frequency is controlled at 100 times / min.

[0105] 3) Continuous extrusion: In terms of tooling, the above-mentioned guide pads and cavity back cover are used. In terms of extrusion die size, a die with a thickness of 41.6mm and a width of 181.5mm is selected. The die sizing band length is 8mm. During the continuous extrusion start-up process, a 25mm diameter upper copper rod is used. The total length of the upper rod is 1m. The heating temperature is 600℃, the baking time is 10min, and the extrusion speed is controlled at 5rpm.

[0106] 4) Drawing: The drawing speed during the production process is controlled at 20m / min.

[0107] 5) Inspection: Inspect the final product's dimensional accuracy, hardness, tensile strength, elongation, density, straightness, and flatness.

[0108] 6) Packaging and warehousing: Packaging and warehousing.

[0109] The specific process parameter control for Example 1 and Comparative Examples 1-8 is shown in Table 1.

[0110] Table 1 Key Processes and Tooling Controls in Embodiments of the Invention

[0111]

[0112] The copper busbars prepared in eight examples and one comparative example were tested, including dimensional tolerances, Brinell hardness, tensile strength, elongation, density, straightness, and flatness. The test methods are as follows:

[0113] Dimensional tolerance tests were conducted in accordance with GB / T4909.2-2009 Bare Wire Test Methods Part 2: Dimensional Measurement.

[0114] The hardness test was conducted according to the Brinell method in GB / T 4909.8 Bare Wire Test Methods Part 8: Hardness Test. The sample length was 10 mm, and the average hardness at the middle and edge of the copper busbar cross-section was measured.

[0115] The tensile strength and elongation tests were conducted in accordance with GB / T 228.1-2010 Metallic materials, tensile testing - Part 1: Test method at room temperature, and were performed on an electronic universal mechanical performance testing machine.

[0116] Density testing was conducted according to GB / T1423-1996, "Test Methods for Density of Precious Metals and Their Alloys". A 100mm sample was taken along the length direction.

[0117] The straightness and flatness tests were conducted according to the straightness test method in GB / T5585.1-2018 Electrical Busbars of Copper, Aluminum and Their Alloys - Part 1: Copper and Copper Alloy Busbars.

[0118] The performance test results of each embodiment and comparative example are shown in Table 2.

[0119] Table 2. Testing performance of various embodiments of the present invention

[0120]

[0121] Based on the above performance test results, it can be seen that the U-shaped copper busbar product prepared according to the requirements of Example 1 of this invention has higher dimensional accuracy, reaching within 0.1 mm; higher density, with the product density reaching 8.96 g / cm2 after extrusion and drawing; more balanced performance in hardness, tensile strength, and elongation, maintaining a high level of elongation even with high hardness and tensile strength, and the mechanical properties of the product meet the expected targets; and high flatness and parallelism accuracy, with straightness values ​​reaching 0.12 and 0.15 mm / m, respectively. All of the above performance requirements meet the expected requirements of the slider guide groove product.

[0122] The test data from Case 2 to Case 8 show that changing any parameter has a certain impact on product performance, and the impact may be one or more factors.

[0123] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. An extrusion fixture for an ultra-wide U-shaped copper busbar, characterized in that, include: A cavity rear cover, wherein the cavity rear cover has a communicating receiving cavity and a rear cover hole; An extrusion die is disposed within the receiving cavity, and the periphery of the receiving cavity covers the outer periphery of the extrusion die. The extrusion die has a die hole inside. A flow guide pad, at least a portion of which is disposed within the receiving cavity, and the periphery of the receiving cavity covers at least a portion of the periphery of the flow guide pad. The flow guide pad presses against the extrusion mold in a first direction so that the extrusion mold abuts against the rear cover of the cavity. The flow guide pad has flow guide holes. The flow guide hole, the mold hole, and the rear cover hole are connected sequentially along the first direction; The central axis of the die hole is parallel to the central axis of the extrusion die along the first direction; The cross-sections of the flow guide hole, the mold hole, and the rear cover hole are all U-shaped. The die hole includes a conical hole and a sizing hole that are interconnected along the first direction. The guide hole, the conical hole, the sizing hole and the rear cover hole are connected in sequence along the first direction. The depth l of the sizing hole is 1 / 6 to 1 / 4 of the total depth L of the die hole. The conical hole includes: a bottom conical hole of the mold and side conical holes of the mold at both ends, the two side conical holes of the mold being located on one side of the bottom conical hole of the mold, and the central axis of the extrusion mold being located on the other side of the bottom conical hole of the mold.

2. The extrusion fixture for the ultra-wide U-shaped copper busbar according to claim 1, characterized in that, The taper α of the bottom conical hole of the mold is 5°~8°, and the taper β of the side conical hole of the mold is 10°~20°.

3. The extrusion fixture for the ultra-wide U-shaped copper busbar according to claim 2, characterized in that, The guide hole includes: a guide center hole and guide side holes at both ends thereof, wherein the cross-sectional area of ​​the guide side holes is 4.5-5.5 times that of the cross-sectional area of ​​the guide center hole.

4. The extrusion fixture for the ultra-wide U-shaped copper busbar according to claim 3, characterized in that, The flow guide pad includes: a back pad, side pads disposed on both sides of the back pad, and a middle pad disposed between the two side pads, wherein the flow guide hole is formed between the back pad, the two side pads and the middle pad.

5. A method for preparing an ultra-wide U-shaped copper busbar, characterized in that, The preparation method using the extrusion fixture of the ultra-wide U-shaped copper busbar according to any one of claims 1 to 4 includes: Step S1: Smelting: Select single-layer electrolytic plates with a copper content of 99.98wt% or more as raw materials. Before adding them to the furnace, the electrolytic plates need to be hoisted 20-30cm above the melting furnace opening and baked for 1-3 minutes. After baking and heating, they can be added to the melting furnace. Step S2: Upward continuous casting: The diameter of the traction copper rod is 23-24.2mm, the traction speed is 300-400mm / min, the pitch is 3-3.5mm, the traction frequency is 105-115 times / min, and the reverse thrust is 0.1-0.2mm / time; Step S3: Continuous extrusion: The continuous extruder uses an upper copper rod with a diameter of 23-24.2mm as the extrusion material and also as the guide rod. The total length of the guide rod must be more than 1.8m. The baking temperature is 650-700℃, the baking time of the guide rod is 15-20min, the rotation speed is 3.5-4rpm, and the extrusion current is 600-700A. Step S4: Pulling: Maintain the pulling speed at 5-10 m / min.

6. The method for preparing the ultra-wide U-shaped copper busbar according to claim 5, characterized in that, In step S4: A drawing fixture is used during the drawing process. The drawing fixture includes a bridge mold and a finished product mold. There is a distance of 1.5-2m between the bridge mold and the finished product mold.

7. The method for preparing the ultra-wide U-shaped copper busbar according to claim 5, characterized in that, Also includes: Step S5: Inspection: Inspect the final product for dimensional accuracy, hardness, tensile strength, elongation, density, straightness, and flatness. Step S6: Packaging and warehousing.

Images