A continuous extrusion processing technology of rare earth Y modified oxygen-free copper

Abstract

The application discloses a continuous extrusion processing technology of rare earth Y modified oxygen-free copper, and belongs to the technical field of copper material processing. The processing technology takes 99.99% cathode copper and 0.006% rare earth Y as raw materials, and is processed through the following steps: argon protection smelting, 500 DEG C * 1.5h ingot homogenizing annealing, multi-pass cold rolling, control of the parameters of the cold rolling, preparation of a strip blank, continuous extrusion of the strip blank under the preheating of an inner cooling die with an inlay cavity and a water-cooled extrusion wheel at 500 DEG C, water quenching after the extrusion, 500 DEG C * 0.5h annealing, finishing to a target size, and making the straightness of the finished product less than or equal to 0.5mm / m. Through the synergistic optimization of rare earth purification, temperature control deformation and rapid annealing, the application realizes the comprehensive jump of the strength, conductivity and corrosion resistance of the oxygen-free copper. Therefore, the application solves the technical problems of how to improve the conductivity and corrosion resistance of the copper material.

Description

Technical Field

[0001] This invention relates to the technical field of copper processing, and in particular to a continuous extrusion process for rare earth Y-modified oxygen-free copper. Background Technology

[0002] Currently, copper production processes are developing towards higher efficiency, lower consumption, greater economic benefits, and environmental friendliness. Although the continuous extrusion process for copper processing has a relatively short lifespan, industrialized production of copper flat wire, copper rods, copper strips, and other products has been achieved, yielding significant economic and social benefits. Continuous extrusion technology in copper processing is simpler than traditional processes and results in smaller interatomic gaps. This technology has been widely applied in wire processing in China. Multi-directional continuous extrusion can improve the thermoplasticity of copper products, enabling the production of copper parts with complex structures or high requirements for product wall surfaces. It also meets processing requirements during actual use and effectively improves the thermodynamic properties of the products.

[0003] Based on this, Chinese patent document CN115376758A discloses a production process for high-strength copper-chromium-zirconium contact wire, which includes the following steps: preparing copper-chromium-zirconium rods → continuous extrusion → primary cold working → heat treatment → secondary cold working; in continuous extrusion, a compaction wheel presses the copper-chromium-zirconium rod into the extrusion groove of the extrusion wheel, and the rotation of the extrusion wheel carries the copper-chromium-zirconium rod into the extrusion die to extrude the copper-chromium-zirconium contact wire; the extrusion groove is U-shaped, the groove wall is smooth, and the top of the extrusion groove is symmetrically rounded. The technical solution disclosed in this patent document, by smoothing the groove wall of the extrusion wheel and rounding the groove opening, facilitates the overflow of extrusion waste, reduces extrusion pressure, and lowers the extrusion temperature. Simultaneously, air cooling of the extrusion wheel groove further reduces the extrusion temperature, keeping it within a low range. This results in less alloy element precipitation during extrusion, lower conductivity of the extruded product, and greater benefits for improving product strength during subsequent aging.

[0004] However, existing high-strength copper-chromium-zirconium contact wire production processes still suffer from technical problems such as the inability to improve the conductivity and corrosion resistance of copper. Specifically, existing technologies mainly involve smoothing the extrusion wheel groove walls and rounding the groove openings to facilitate the overflow of extrusion waste, reduce extrusion pressure, and lower extrusion temperature. This results in less alloying element precipitation during extrusion, leading to lower conductivity in the extruded product. In practical applications, due to the complexity of cable laying environments and limited space, copper wire cores used in cables often require bending, rotation, and other deformation processes to meet design and installation requirements. However, the outer surface of bent sections of the copper wire core is prone to surface micro-cracks, and flattened sections are prone to poor flatness. This not only affects service life but also negatively impacts the wire core's heat dissipation and corrosion resistance, becoming a pressing technical problem in the copper wire core processing industry. Summary of the Invention

[0005] Therefore, it is necessary to provide a continuous extrusion process for rare earth Y-modified oxygen-free copper to address technical issues such as how to improve the electrical conductivity and corrosion resistance of copper materials.

[0006] A continuous extrusion process for rare earth Y-modified oxygen-free copper includes the following steps: using cathode copper and rare earth elements as raw materials, smelting under argon protection, homogenizing and annealing the ingot, and preparing a strip billet through multiple cold rolling passes; then, continuously extruding the strip billet under preheating at 500°C using an internal cooling die, followed by water quenching and annealing at 500°C for 0.5 hours; finally, refining the copper material to the preset dimensions.

[0007] Furthermore, a continuous extrusion process for rare earth Y-modified oxygen-free copper includes the following steps:

[0008] S1: Raw material preparation:

[0009] a. Ingredients: Take 99.99% pure cathode copper plates and add 0.006% Y by mass; or use a pre-set formula;

[0010] b. Melting: Melting in a vacuum medium-frequency induction furnace, with argon gas for protection, flow rate 10L / min, temperature controlled at 1150–1180℃; Melt refining: Add 0.01% charcoal covering layer to adsorb impurities, hold for 30 minutes and then skim off the slag;

[0011] c. Ingot casting: Pour into a copper mold preheated to 300℃ to form an ingot with a length × width × thickness of 40mm × 20mm × 3mm; the cooling rate of the ingot is ≥50℃ / s;

[0012] d. Homogenization annealing: annealing in a box furnace at 500℃ for 1.5h → cooling in the furnace to 200℃ followed by air cooling;

[0013] S2: Pre-extrusion treatment:

[0014] a. Cold rolling deformation: The ingot undergoes multiple cold rolling passes, with a total strain η=2.5, corresponding to a cross-sectional area reduction rate of 92%. Formula: , A represents the initial cross-sectional area of ​​the ingot before cold rolling, in mm²; A represents the final cross-sectional area of ​​the material after cold rolling, in mm²; η represents the actual strain; control point: deformation per pass ≤ 20%;

[0015] b. Pickling and drying: Pickling solution: 10% H2SO4 + 5% H2O2, soak at room temperature for 5 min → rinse with deionized water; drying: process in an 80℃ hot air circulating drying oven for 20 min;

[0016] c. End welding: The ends of the rolled plates are butted together to form a continuous strip using argon arc welding, with weld strength ≥ 90% of the base material; anti-fracture design: the weld area is ground into a 30° bevel transition.

[0017] S3: Continuous extrusion:

[0018] a. Mold assembly: Improved tooling is used: embedded cavity and internally cooled extrusion wheel; Φ10mm water channel is provided between the side body and the workpiece; the water inlet and outlet channels of the internally cooled baffle block are Φ4mm and the angle is 17°;

[0019] b. Mold preheating: Close the extension slot gate, resistance heat to 500℃±10℃, and then keep warm for 1 hour;

[0020] c. Extrusion parameters: Extrusion temperature set to 400–450℃; Cooling water flow rate set to 20L / min at room temperature;

[0021] S4: Cooling Annealing

[0022] a. Online water cooling: A spray ring is installed at the extrusion outlet, with a water temperature of 10–15℃ and a cooling rate of >100℃ / s;

[0023] b. Finished product annealing: 500℃×0.5h continuous annealing furnace treatment → nitrogen protection;

[0024] c. Cooling method: Air cooling after annealing;

[0025] S5: Finishing:

[0026] a. Cold rolling / drawing: Annealed strip is thinned by 20–30% through a four-high finishing mill to a target thickness of ±0.01mm; or it is processed into Φ3–12mm wire by an inverted drawing machine with a die angle of 12°, so that its surface roughness Ra≤0.8μm;

[0027] b. Precision sawing: Double-headed circular saw cutting, length 3–4m → tolerance ±1mm, real-time calibration using a laser rangefinder;

[0028] c. Straightening and shaping: Double-plane roller straightener: roller gap 50mm, pressure 8MPa → straightness ≤0.5mm / m; surface polishing: fiber wheel + diamond plaster, roughness Ra≤0.2μm.

[0029] Specifically, the rare earth modified oxygen-free copper formulation in Example 1 is as follows by mass: base copper: 99.995% cathode copper; modifiers: 0.003% Y, 0.001% Ag and 0.0005% B.

[0030] Specifically, the formula of rare earth modified oxygen-free copper in Example 2 is as follows by mass: base copper: 99.99% oxygen-free copper; modifiers: 0.006% Y, 0.008% Sn and 0.002% Zr.

[0031] Specifically, the rare earth modified oxygen-free copper formulation in Example 3 is as follows by mass: base copper: 99.97% low oxygen copper; modifier: 0.005% Y, 0.003% La, 0.015% Fe and 0.002% P.

[0032] Specifically, the formula of rare earth modified oxygen-free copper in Example 4 is as follows by mass: base copper: 99.99% oxygen-free copper; modifier: 0.004% Y, 0.0003% C nanotubes and 0.001% Gd.

[0033] Furthermore, in Example 1 above, the copper material is rapidly solidified after melting, and its cooling rate is controlled to be ≥100℃ / s to suppress Ag segregation; the parameters for annealing the finished product are set to 350℃×2h to activate the grain boundary strengthening effect of B.

[0034] Furthermore, in Example 2 above, the copper material is continuously cast and rolled, and then tin is plated on the surface of the copper material to control the Sn layer thickness to 5μm; the annealing process parameters are set as follows: 400℃×1h→water quenching, retaining Sn solid solution strengthening.

[0035] Furthermore, in Example 3 above, the copper material is extruded and then subjected to deformation heat treatment: cold rolling 50% → annealing at 450℃ for 0.5h → second cold rolling 20%; the Fe / Y mass ratio is controlled to avoid excessive Fe from damaging conductivity.

[0036] Furthermore, in Example 4 above, copper material was prepared by powder metallurgy: copper powder + Y-Gd alloy powder + C nanotubes → cold isostatic pressing → sintering → extrusion; the parameters for annealing the finished product were controlled as follows: 480℃ × 15min, to short-term activate the magnetic stabilizing effect of Gd.

[0037] In summary, this invention discloses a continuous extrusion process for rare earth Y-modified oxygen-free copper. Using 99.99% cathode copper and 0.006% rare earth Y as raw materials, the process involves argon-protected melting, ingot homogenization annealing at 500℃ for 1.5 hours, followed by multi-pass cold rolling with total strain η=2.5 and cross-sectional area reduction of 92%. A strip billet is then prepared and continuously extruded at 500℃ using an internally cooled die with embedded cavities and water-cooled extrusion rollers. After extrusion, the strip is water-cooled, quenched, and annealed at 500℃ for 0.5 hours. Finally, the strip is finished to the target dimensions, ensuring a straightness of ≤0.5mm / m. The beneficial effects of this invention are as follows: Improved conductivity: reaching 102.8% IACS, which is 2.8% higher than pure copper, reducing cable transmission losses; Resistance to high-temperature softening: annealing hardness reduction rate is only 56.5%, which is 8.4% lower than pure copper's 61.7%, making it suitable for high-temperature applications; Enhanced corrosion resistance: corrosion current density is 5.017 μA / cm², 40% lower than pure copper, extending the service life of submarine cables; High yield: 93%, 8% higher than traditional processes, saving costs. This invention's continuous extrusion process for rare-earth Y-modified oxygen-free copper achieves a comprehensive leap in the strength, conductivity, and corrosion resistance of oxygen-free copper through the synergistic optimization of rare-earth purification, temperature-controlled deformation, and rapid annealing. Therefore, this invention's continuous extrusion process for rare-earth Y-modified oxygen-free copper solves the technical problems of how to improve the conductivity and corrosion resistance of copper materials. Attached Figure Description

[0038] Figure 1 This is a process flow diagram for a continuous extrusion process. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] Specifically, the present invention provides a continuous extrusion process for rare earth Y-modified oxygen-free copper, which includes the following steps:

[0046] S1: Raw material preparation, using cathode copper, that is, copper material with a copper content of not less than 99.99% and rare earth elements, for example, 0.006% Y master alloy → smelting → ingot casting → homogenization annealing at 500℃ for 1.5h;

[0047] S2: Pre-extrusion treatment, cold rolling of ingot to strain η=2.5 → pickling and drying → welding of ends (to prevent breakage);

[0048] S3: Continuous extrusion, using an improved die (internal cooling roller + baffle block) → preheating to 500℃;

[0049] S4: Cooling annealing, water cooling directly after extrusion → 500℃×0.5h finished product annealing → air cooling;

[0050] S5: Finishing process, cold rolling / drawing to preset size → sawing (tolerance ±1mm) → double-plane straightening (straightness ≤0.5mm / m).

[0051] Specifically, in the continuous extrusion processing of rare earth Y-modified oxygen-free copper according to the present invention, the rare earth modified raw material, namely, 0.006% rare earth Y (mass fraction) is added during the oxygen-free copper smelting stage and introduced through Cu-Y master alloy; the function of this process is to: purify the copper liquid, reduce impurities such as Fe and O, and improve the conductivity of the copper material to not less than 101% IACS; refine the grains, enhance the resistance to high-temperature softening, and reduce the hardness reduction rate of the copper material after annealing by more than 5%; improve corrosion resistance, and reduce the corrosion current density of the copper material by 40%; at the same time, the impedance value of the copper material is increased by 129%.

[0052] For details, please refer to Figure 1 In this invention, the technical principle of the continuous extrusion fixture for copper processing is mainly based on the friction between the extrusion rollers and the material's interior, converting the generated power into output power to the material. Compared with conventional processing and forming methods, continuous extrusion can achieve smoother cross-section cutting, exhibiting significant advantages in copper production and making it a preferred production technology. Figure 1As shown, the preparation process before extrusion is quite complicated and crucial. First, the copper raw material is roughly processed to a standard state. After being washed and dried, the cleanliness of the copper material is maintained. The modified regular rectangular ends are welded into the cylinder. The same pressure is applied evenly and slowly to both ends, or opposite pressure is applied to the top and bottom at the same time, so that the positive pressure and reaction force are balanced, thereby preventing the copper material from being cut off. At the same time, continuous extrusion can make the movement between atoms in the copper material more frequent, and the forming surface is smoother.

[0053] Specifically, in this invention, a preliminary design using a planar pattern can be used. At this stage, the cross-sectional area of ​​the copper product, its side length, and the feeding method need to be comprehensively considered, primarily focusing on the displacement of the copper material within the extrusion mold. Therefore, the sizing side length of the continuous extrusion die for copper processing can be defined as approximately 3–6 mm. However, because copper has poor corrosion resistance and is relatively soft, it is essential to ensure its proper shaping during long-term extrusion processing, and the end center point should be offset from the central axis of the extrusion chamber.

[0054] Furthermore, during the design of continuous extrusion tooling dies for copper processing, the area of ​​the extension groove can be improved because the aforementioned center point may change during continuous extrusion. This change mainly manifests as positional shifts and uncertainties in length, which may lead to certain limitations in the continuous extrusion tooling dies during copper product processing.

[0055] Furthermore, installing a ring die at the front end of the copper material can suppress the movement of metal molecules and also allow the copper material to diffuse to a certain extent. By continuously squeezing the copper in an irregular shape on the transverse cross section, the pressure ring can weaken the activity of copper molecules in the core, thereby transferring the metal molecules to places where transverse buckling is unlikely.

[0056] Furthermore, during the improvement of the continuous extrusion tooling for copper processing, it is necessary to improve the preheating process. The two doors of the extension groove can be closed to heat the continuous extrusion die to a high temperature, keeping the temperature at both ends of the extension groove consistent. Due to the improved temperature control, the activity between alloy atoms will also be significantly improved, which can effectively reduce the imbalance problem in the continuous extrusion process and improve production efficiency.

[0057] In summary, the continuous extrusion process for rare earth Y-modified oxygen-free copper of this invention can employ an embedded cavity: that is, a split heat-shrink structure is adopted, the cavity is made of high-temperature nickel-based alloy, and the substrate is made of H13 steel, thereby reducing the cost by about 60%.

[0058] In addition, for internally cooled extrusion rollers / stop blocks: a 6-20mm round hole water channel can be provided between the side body of the extrusion roller and the workpiece for water cooling; the stop block is designed with a 2-6mm diameter water inlet / outlet channel with an angle between 15° and 18°. The purpose of this design is to reduce the working temperature by 30%, reduce thermal deformation damage, and extend the mold life.

[0059] Furthermore, the key process parameters optimization measures for the continuous extrusion processing of rare earth Y-modified oxygen-free copper of the present invention are as follows: a. Preheating: The die is preheated to 500°C, and the temperature at both ends of the extension groove is uniform to reduce extrusion imbalance; b. Pulling force ≤25kN to avoid excessive grain deformation; c. Cooling: The water temperature of the internal cooling system is ≤25°C to ensure that the surface temperature of the extrusion roller is <200°C; d. Post-treatment: The finished product is annealed at 500°C for 0.5h immediately after extrusion to activate the rare earth strengthening effect.

[0060] Furthermore, a specific embodiment of the continuous extrusion processing technology for rare earth Y-modified oxygen-free copper of the present invention is as follows:

[0061] S1: Raw material preparation:

[0062] a. Ingredients: Take 99.99% pure cathode copper plate with an oxygen content ≤5ppm, and add 0.006% Y by mass ratio, which can be introduced through Cu-12%Y master alloy;

[0063] For example, 60g of Y can be added to 1 ton of cathode copper, which is equivalent to 0.5kg of Cu-12%Y master alloy;

[0064] b. Melting: Melting in a vacuum medium-frequency induction furnace, with argon gas for protection, flow rate 10L / min, temperature controlled at 1150–1180℃; Melt refining: Add 0.01% charcoal covering layer to adsorb impurities, hold for 30 minutes and then skim off the slag;

[0065] c. Ingot casting: Pour into a copper mold preheated to 300℃ to form an ingot with a length × width × thickness of 40mm × 20mm × 3mm; cooling rate ≥ 50℃ / s to prevent rare earth segregation;

[0066] d. Homogenization annealing: annealing in a box furnace at 500℃ for 1.5h → cooling in the furnace to 200℃ followed by air cooling; its function is to eliminate dendrite segregation and make Y element diffuse uniformly.

[0067] S2: Pre-extrusion treatment:

[0068] a. Cold rolling deformation: The ingot undergoes multiple cold rolling passes, with a total strain η=2.5, corresponding to a cross-sectional area reduction rate of 92%. Formula: , A represents the initial cross-sectional area of ​​the ingot before cold rolling, in mm²; A represents the final cross-sectional area of ​​the material after cold rolling, in mm²; η represents the true strain (logarithmic strain); control point: deformation per pass ≤ 20% to prevent edge cracking;

[0069] b. Pickling and drying: Pickling solution: 10% H2SO4 + 5% H2O2, soak at room temperature for 5 min → rinse with deionized water; drying: process in an 80℃ hot air circulating drying oven for 20 min;

[0070] c. End welding: The ends of the rolled plates are butted together to form a continuous strip using argon arc welding, with weld strength ≥ 90% of the base material; anti-fracture design: the weld area is ground into a 30° bevel transition.

[0071] S3: Continuous extrusion:

[0072] a. Mold assembly: Use improved tooling: insert-type cavity, such as high-temperature nickel-based alloy insert + H13 steel base; internally cooled extrusion wheel, such as a Φ10mm water channel between the side body and the workpiece; internally cooled baffle block, such as a Φ4mm water inlet and outlet channel with an angle of 17°.

[0073] b. Mold preheating: Close the extension slot gate, resistance heat to 500℃±10℃, and then keep it at that temperature for 1 hour to ensure uniform temperature;

[0074] c. Extrusion parameters: Rare earth elements are used to refine grains and improve plasticity; the extrusion temperature is set to 400–450℃, which is lower than that of pure copper (480℃), and rare earth elements reduce the recrystallization temperature; the cooling water flow rate is set to 20L / min (≤25℃) to ensure that the surface temperature of the extrusion roller is <200℃.

[0075] S4: Cooling Annealing

[0076] a. Online water cooling: A spray ring is installed at the extrusion outlet, with a water temperature of 10–15℃ and a cooling rate >100℃ / s, to suppress grain growth;

[0077] b. Finished product annealing: 500℃×0.5h continuous annealing furnace treatment → nitrogen protection (oxygen content ≤50ppm); Mechanism: activate the grain boundary pinning effect of rare earth Y to reduce its hardness reduction rate to 56.5%; eliminate processing stress and improve conductivity to 102.8% IACS or above.

[0078] c. Cooling method: Air cooling after annealing to avoid residual stress caused by water cooling;

[0079] S5: Finishing:

[0080] a. Cold rolling / drawing: Annealed strip is thinned by 20–30% through a four-high finishing mill to a target thickness of ±0.01mm; or it is processed into Φ3–12mm wire by an inverted drawing machine with a die angle of 12°, so that its surface roughness Ra≤0.8μm;

[0081] b. Precision sawing: Double-headed circular saw cutting, length 3–4m → tolerance ±1mm, real-time calibration using a laser rangefinder;

[0082] c. Straightening and shaping: Double-plane roller straightener: roller gap 50mm, pressure 8MPa → straightness ≤0.5mm / m; surface polishing: fiber wheel + diamond paste, roughness Ra≤0.2μm, to improve the adhesion of the cable insulation layer.

[0083] Specifically, in the above embodiments, key process control points include: In the raw material smelting step, the Y content is controlled at 0.006% ± 0.0005%, which can be confirmed using ICP-OES spectral analysis. In the cold rolling step, the strain η = 2.5, corresponding to a material thickness of 1.5 mm; online feedback can be provided using a laser thickness gauge. In the extrusion step, the wheel surface temperature is controlled to ≤200℃; real-time monitoring can be achieved using an infrared thermal imager. In the annealing step, the grain size is controlled to 15–20 μm, which can be detected using EBSD electron backscatter diffraction. In the finishing step, the straightness is controlled to ≤0.5 mm / m, which can be detected using an optical projector + three-point bending test.

[0084] Furthermore, after adopting a specific embodiment of the continuous extrusion processing technology for rare earth Y-modified oxygen-free copper of the present invention, the improved effect is shown in Table 1 below.

[0085] Table 1: Empirical data on the process of the present invention (performance comparison (0.006% Y-modified oxygen-free copper vs. pure oxygen-free copper))

[0086]

[0087] Moreover, by using the aforementioned continuous extrusion process for rare earth Y-modified oxygen-free copper of the present invention, the yield of copper material can reach 93%, which is 8% higher than the 85% yield of the traditional process.

[0088] Furthermore, in the continuous extrusion processing technology of rare earth Y-modified oxygen-free copper of the present invention, the following specifically discloses examples of different raw material ratios used in the aforementioned step S1, as follows:

[0089] Example 1: Superconducting creep-resistant cable core, suitable for high-voltage power transmission

[0090] formula:

[0091] Base copper: 99.995% ultra-high purity cathode copper;

[0092] Modifiers: 0.003% Y, to purify impurities and improve conductivity; 0.001% Ag, to inhibit grain boundary migration and increase recrystallization temperature; 0.0005% B, to refine grains and pin dislocations.

[0093] Key process steps in Example 1: After melting, rapid solidification is required, and the cooling rate should be controlled at ≥100℃ / s to suppress Ag segregation; Finished product annealing: 350℃×2h to activate the grain boundary strengthening effect of B.

[0094] Experimental data from Example 1:

[0095]

[0096] Example 2: Deep-sea corrosion-resistant flexible cable, which is particularly suitable for submarine cables.

[0097] Formula: Base copper: 99.99% oxygen-free copper

[0098] Modifiers: 0.006% Y, to form a dense Y2O3 film that blocks Cl⁻ corrosion; 0.008% Sn, to improve work hardening rate and enhance strength; 0.002% Zr, to form a nano ZrCu5 phase that inhibits seawater corrosion.

[0099] Key process steps in Example 2: tin plating on the surface after continuous casting and rolling, controlling the Sn layer thickness to 5μm, synergistically improving corrosion resistance; annealing process: 400℃×1h→water quenching, retaining Sn solid solution strengthening.

[0100] Experimental data from Example 2:

[0101]

[0102] Example 3: High-strength fatigue-resistant robot cable, suitable for industrial robot joints, etc.

[0103] formula:

[0104] Base copper: 99.97% low-oxygen copper (O element ≤10ppm)

[0105] Modifiers: 0.005% Y + 0.003% La, composite rare earth to refine grains; 0.015% Fe, to form Fe-Y precipitates to improve strength; 0.002% P, to deoxidize and improve flowability.

[0106] Key process steps in Example 3: Post-extrusion deformation heat treatment: 50% cold rolling → annealing at 450℃ for 0.5h → 20% secondary cold rolling; control the Fe / Y mass ratio ≈3 to avoid excessive Fe damaging electrical conductivity.

[0107] Experimental data from Example 3:

[0108]

[0109] Example 4: Superconducting energy-saving new energy vehicle cable, suitable for 800V high-voltage platforms.

[0110] Formula: Base copper: 99.99% oxygen-free copper;

[0111] Modifiers: 0.004% Y, to optimize the balance between conductivity and strength; 0.0003% C nanotubes, to enhance current carrying capacity and provide directional dispersion; 0.001% Gd, to provide magnetothermal stability and suppress high-frequency eddy currents.

[0112] Key process steps of Example 4: Powder metallurgy preparation: copper powder + Y-Gd alloy powder + C nanotubes → cold isostatic pressing → sintering → extrusion; Finished product annealing: 480℃×15min, short-term activation of the magnetic stabilizing effect of Gd.

[0113] Experimental data from Example 4:

[0114]

[0115] Furthermore, the performance of the aforementioned Example 1 was compared with that of traditional copper cable materials, and the experimental structure is shown in Table 2 below:

[0116] Table 2: Performance Comparison of Example 1 and Traditional Cable Copper Material

[0117]

[0118] As shown in Table 2 above, the continuous extrusion process of rare earth Y-modified oxygen-free copper of the present invention, through precise rare earth ratio and synergistic nano / composite reinforcement, can break through the bottlenecks of strength, corrosion resistance and fatigue of cable materials while ensuring conductivity, and meet the extreme performance requirements of copper conductors in emerging fields.

[0119] In summary, this invention discloses a continuous extrusion process for rare earth Y-modified oxygen-free copper. Using 99.99% cathode copper and 0.006% rare earth Y as raw materials, the process involves argon-protected melting, ingot homogenization annealing at 500℃ for 1.5 hours, followed by multi-pass cold rolling with total strain η=2.5 and cross-sectional area reduction of 92%. A strip billet is then prepared and continuously extruded at 500℃ using an internally cooled die with embedded cavities and water-cooled extrusion rollers. After extrusion, the strip is water-cooled, quenched, and annealed at 500℃ for 0.5 hours. Finally, the strip is finished to the target dimensions, ensuring a straightness of ≤0.5mm / m. The beneficial effects of this invention are as follows: Improved conductivity: reaching 102.8% IACS, which is 2.8% higher than pure copper, reducing cable transmission losses; Resistance to high-temperature softening: annealing hardness reduction rate is only 56.5%, which is 8.4% lower than pure copper's 61.7%, making it suitable for high-temperature applications; Enhanced corrosion resistance: corrosion current density is 5.017 μA / cm², 40% lower than pure copper, extending the service life of submarine cables; High yield: 93%, 8% higher than traditional processes, saving costs. This invention's continuous extrusion process for rare-earth Y-modified oxygen-free copper achieves a comprehensive leap in the strength, conductivity, and corrosion resistance of oxygen-free copper through the synergistic optimization of rare-earth purification, temperature-controlled deformation, and rapid annealing. Therefore, this invention's continuous extrusion process for rare-earth Y-modified oxygen-free copper solves the technical problems of how to improve the conductivity and corrosion resistance of copper materials.

[0120] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A continuous extrusion processing technology for rare earth Y-modified oxygen-free copper, characterized in that, The steps include: using cathode copper and rare earth element γ as raw materials, smelting under argon protection, homogenizing and annealing the ingot, and preparing strip blanks through multiple cold rolling passes; then, continuously extruding using an internal cooling die at 500℃ preheating, followed by water quenching and annealing at 500℃ for 0.5 hours; finally, refining the copper material to the preset dimensions; the specific steps are as follows: S1: Raw material preparation: a. Ingredients: Take 99.99% pure cathode copper plates and add 0.006% rare earth element Y by mass ratio; b. Melting: Melt in a vacuum medium-frequency induction furnace, with argon gas for protection, flow rate 10L / min, temperature controlled at 1150-1180℃; add 0.01% charcoal covering layer to adsorb impurities, hold for 30min and then skim off the slag; c. Ingot casting: Pour into a copper mold preheated to 300℃ to form an ingot with a length × width × thickness of 40mm × 20mm × 3mm; the cooling rate of the ingot is ≥50℃ / s; d. Homogenization annealing: Annealing in a box furnace at 500℃ for 1.5h, followed by air cooling after the furnace cools to 200℃; S2: Pre-extrusion treatment: a. Cold rolling deformation: The ingot undergoes multiple cold rolling passes, with a total strain η=2.5, corresponding to a cross-sectional area reduction rate of 92%. Formula: , A represents the initial cross-sectional area of ​​the ingot before cold rolling, in mm²; A represents the final cross-sectional area of ​​the material after cold rolling, in mm²; η represents the actual strain; control point: deformation per pass ≤ 20%; b. Pickling and drying: Pickling solution: 10% H2SO4 + 5% H2O2, soak at room temperature for 5 minutes, then rinse with deionized water; treat in an 80℃ hot air circulating drying oven for 20 minutes; c. End welding: The ends of the rolled plates are butted together to form a continuous strip using argon arc welding. The weld strength is ≥90% of the base material, and the weld area is ground into a 30° bevel transition. S3: Continuous extrusion: a. Mold assembly: Uses embedded cavity and internal cooling extrusion roller; Φ10mm water channel between side body and workpiece; water inlet and outlet channel of internal cooling baffle block Φ4mm, angle 17°; b. Mold preheating: Close the extension slot gate, resistance heat to 500℃±10℃, and then keep warm for 1 hour; c. Extrusion parameters: Extrusion temperature is set to 400-450℃; cooling water flow rate is set to 20L / min at room temperature; S4: Cooling Annealing a. Online water cooling: A spray ring is installed at the extrusion outlet, with a water temperature of 10-15℃ and a cooling rate of >100℃ / s; b. Finished product annealing: 500℃×0.5h continuous annealing furnace treatment, nitrogen protection; c. Cooling method: Air cooling after annealing; S5: Finishing: a. Cold rolling / drawing: Annealed strip is rolled by a four-high finishing mill with a thinning rate of 20-30% and a target thickness of ±0.01mm; or it is processed into Φ3-12mm wire by an inverted drawing machine with a die angle of 12°, so that its surface roughness Ra≤0.8μm; b. Precision sawing: Double-headed circular saw cutting, length 3-4m, tolerance ±1mm, real-time calibration using a laser rangefinder; c. Straightening and shaping: Double-plane roller straightener: roller gap 50mm, pressure 8MPa, straightness ≤0.5mm / m; surface polishing: fiber wheel with diamond paste, roughness Ra≤0.2μm.

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