A short process rolling and drawing method for preparing an external profiled copper slot wire for WIC wire

Abstract

This invention belongs to the field of superconducting material processing technology, and relates to a short-process rolling and drawing method for preparing externally coated shaped copper grooved wires for WIC lines. The method includes: annealing a semi-finished round wire under a protective atmosphere, followed by straightening the annealed wire; coating the surface of the straightened wire with a lubricant, then preheating the wire; feeding the preheated wire into a four-high rolling mill for one-time composite rolling to form a U-shaped cross-section grooved wire; coating the surface of the rolled grooved wire with a lubricant, and drawing the grooved wire to obtain the finished grooved wire. This invention uses specific shaped rolls and a dedicated lubricant to achieve one-time composite rolling, eliminating the need for the lengthy path of multiple rolling passes or sequential deformation of drawing dies required by traditional processes, thus achieving efficient and high-precision one-time forming from a round wire to a U-shaped grooved wire.

Description

Technical Field

[0001] This invention belongs to the field of superconducting material processing technology, and relates to a short-process rolling and drawing method for preparing WIC wires with externally coated irregular copper grooves. Background Technology

[0002] Wire-in-Channel (WIC) superconducting wires are high-performance composite materials made by embedding and welding NbTi / Cu multi-core superconducting wires into specially designed copper channel wires. Due to their high copper-to-superconductor ratio and low processing rate, they are widely used in the manufacture of superconducting magnets for systems such as magnetic resonance imaging (MRI). In this structure, the externally applied shaped copper channel wires not only serve as mechanical support and a protective shell for the superconducting wires, but more importantly, they immediately take over the responsibility of shunting large currents when the superconductor experiences a localized loss of quench due to unforeseen circumstances, thus preventing damage to the magnet. Therefore, the geometrical accuracy, internal metallurgical quality, and uniformity of conductivity of the copper channel wires determine the reliability and stability of the final superconducting wire.

[0003] Currently, traditional techniques for preparing such irregularly shaped copper wire grooves mainly rely on multi-pass rolling or multi-pass drawing die forming processes. These methods reveal significant limitations when faced with the diverse and complex cross-sectional structure requirements of wire grooves. The roll debugging process before production is time-consuming, and during production, uneven wear or even breakage of the rolls can lead to the scrapping of the entire batch of wire, shortening die life and hindering production efficiency and cost control. Especially for wire grooves with complex cross-sectional shapes, traditional rolling techniques are often inadequate, resulting in long processing cycles and difficulty in achieving high dimensional accuracy standards for the final product. Furthermore, during the drawing process of irregularly shaped wires, the uniformity of workpiece deformation is far less than that of round wires, making it easier to generate uneven residual stress, which can lead to defects such as bending, dimensional deviations, and even localized microcracks in the finished product. Although attempts have been made to improve this problem by optimizing mold design, such as using artificial intelligence and finite element analysis to optimize mold hole shape to achieve load balancing and reduce stress-strain inhomogeneity, the inherent problems of traditional methods still exist for superconducting applications that require consistency and reliability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper grooves. The preparation method provided by the present invention uses a special-shaped roll and a special lubricant to achieve one-time composite rolling, eliminating the need for the lengthy path of multiple rolling passes or sequential deformation of drawing dies required by traditional processes, and achieving efficient and high-precision one-time forming from round wire to U-shaped groove wire.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This invention provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper grooves, the rolling and drawing method comprising:

[0007] The semi-finished round wire was subjected to a first annealing treatment under a protective atmosphere, and then the round wire after the first annealing treatment was straightened.

[0008] The first lubricant is applied to the surface of the straightened round wire, and then the straightened round wire is preheated. The preheated round wire is then fed into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove wire.

[0009] A second lubricant is applied to the surface of the rolled groove, and the groove is drawn using a drawing machine;

[0010] After drawing, the grooved wire undergoes a second annealing process and surface cleaning to obtain the finished grooved wire;

[0011] The four-roll mill includes a top roll at the top of the circular line, a bottom roll at the bottom of the circular line, and support rolls on both sides of the circular line. The surface of the top roll is provided with annular protrusions with a rounded trapezoidal cross-section to form grooves in the grooves.

[0012] The preparation method provided by this invention uses a special irregular structure roll and a special lubricant to achieve one-time composite rolling, eliminating the need for the lengthy path of multiple rolling passes or sequential deformation of drawing dies required by traditional processes, and realizing efficient and high-precision one-time forming from round line to U-shaped groove line.

[0013] Traditional methods for manufacturing irregularly shaped copper channel wires typically require multiple rolling passes or continuous processing with multiple sets of drawing dies. Each additional pass necessitates readjusting the roll gap, dies, and process parameters. This process is not only time-consuming and labor-intensive, but each adjustment also introduces human error or equipment fluctuations, leading to dimensional variations within batches or even between different sections of a single wire. More seriously, during multi-pass deformation, the material repeatedly endures work hardening effects. Even with interspersed annealing processes, it is difficult to completely eliminate accumulated residual stress and microstructure inhomogeneities, resulting in defects such as bending, twisting, or dimensional deviations in the final product. The one-step composite rolling method employed in this invention fundamentally avoids these problems. A four-high rolling mill with specially designed rolls achieves a one-time deformation from round wire to grooved wire. The round wire is subjected to pressure from the top, bottom, and sides by the top roll, bottom roll, and support roll, respectively, directly forming a grooved wire with a U-shaped cross-section. This shortens the processing time from billet to semi-finished product, reduces production interruptions caused by multiple clamping and adjustment, and significantly improves production efficiency. More importantly, since the entire deformation process is completed in one continuous operation, the strain experienced by the material is singular and controllable, which is conducive to obtaining a more uniform grain structure and a more consistent deformation texture. This provides a semi-finished product with better metallurgical quality for the subsequent drawing process, resulting in a final product with high dimensional accuracy and excellent mechanical properties.

[0014] The core technology for achieving one-time composite rolling lies in the unique structure of the four-high rolling mill. This mill is not a simple two- or three-high configuration, but rather includes a top roll, a bottom roll, and support rolls on both sides. This four-roll surround layout provides comprehensive constraint and forming pressure for the circular groove. The top roll has annular protrusions with rounded trapezoidal cross-sections. The rounded corners effectively prevent stress concentration at the root of the groove during rolling, thus preventing the initiation of microcracks. The trapezoidal sidewall angles facilitate smooth metal flow and reduce forming resistance. The bottom roll is responsible for forming the flat bottom surface of the groove, while the support rolls on both sides precisely control the verticality and thickness of the two sidewalls of the groove. Four rollers work together to form a closed forming cavity, ensuring that the round wire can be evenly and stably redistributed and filled into the preset U-shaped space when it passes through. A well-shaped and accurately sized grooved semi-finished product is obtained in one pass, avoiding problems such as incomplete shape, incomplete filling or burrs caused by poor coordination between passes in traditional multi-pass rolling. This ensures the accuracy of the grooved geometric dimensions from the source.

[0015] However, in high-intensity one-time rolling deformation, the enormous pressure and friction can severely affect the durability of the rolls and the surface quality of the round wire. Poor lubrication can lead to rapid wear or even damage to the rolls, increasing production costs, and can also cause defects such as scratches and roughening on the surface of the round wire due to overheating or excessive friction, affecting subsequent processing and the electrical conductivity uniformity of the final product. Therefore, this invention proposes a lubricant specifically designed for one-time rolling processes. This lubricant is not a single component but is prepared by diluting a concentrate as needed. The synthetic ester base oil provides excellent basic lubrication performance and load-bearing capacity. The extreme pressure anti-wear additives include sulfurized olefins, triphenyl thiophosphate, and tributyl phosphate. Under high-temperature and high-pressure rolling conditions, these additives can chemically react with the metal surface to form a tough lubricating film. This film effectively prevents direct contact between the rolls and the surface of the round wire under extreme pressure, preventing welding or scratches, thus playing an extreme pressure anti-wear role. Friction modifiers, including molybdenum dialkyl dithiocarbamate, glyceryl monooleate, and oleic acid, primarily reduce the coefficient of friction, making the round wire deformation process smoother and reducing energy consumption and deformation heat. Antioxidants, including disodium ethylenediaminetetraacetate and L-ascorbic acid, inhibit the oxidative deterioration of the lubricant at high temperatures, extending its service life. Emulsifiers ensure that the oily components are uniformly dispersed in deionized water, forming a stable emulsion. Corrosion inhibitors protect the pure copper round wire from corrosion during processing and storage. This invention's lubricant, designed for one-time composite rolling, forms a stable and efficient protective film at the roll-to-round wire interface, significantly reducing frictional resistance and interface temperature. This protects the expensive and precision-required rolls while ensuring a smooth, undamaged surface for the formed grooved wire, providing excellent surface conditions for subsequent drawing. The lubricant is prepared fresh for each use, ensuring the effectiveness of its active ingredients.

[0016] After obtaining the U-shaped grooved wire semi-finished product through a one-time composite rolling process, the grooved wire undergoes further dimensional fine-tuning, sizing, and surface quality improvement through multiple drawing passes. Because the semi-finished product obtained in the initial rolling stage already possesses a highly regular U-shaped profile and uniform microstructure, the subsequent drawing deformation becomes more stable and controllable. The number of drawing passes is reduced, with a slightly larger deformation rate in the first pass to eliminate minor inhomogeneities occurring during rolling. The deformation rates in the intermediate and final passes gradually decrease to achieve a smooth dimensional transition and improved surface finish. Finally, after multiple drawing passes, annealing is performed to eliminate processing stress, and surface cleaning yields a clean finished grooved wire, ensuring that the final product grooved wire meets the stringent requirements of WIC superconducting wires for geometric dimensional accuracy, internal metallurgical quality, and uniform conductivity.

[0017] As a preferred embodiment of the present invention, the semi-finished round wire is made of pure copper.

[0018] In some optional instances, the diameter of the semi-finished circular wire is 8 to 10 mm, for example, it can be 8.0 mm, 8.2 mm, 8.4 mm, 8.6 mm, 8.8 mm, 9.0 mm, 9.2 mm, 9.4 mm, 9.6 mm, 9.8 mm or 10.0 mm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0019] In some optional instances, the protective atmosphere consists of nitrogen and hydrogen, wherein the volume fraction of hydrogen is 5 to 10%, for example, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, or 10.0%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0020] In some optional instances, the heating rate of the first annealing treatment is 5~10℃ / min, for example, it can be 5.0℃ / min, 5.5℃ / min, 6.0℃ / min, 6.5℃ / min, 7.0℃ / min, 7.5℃ / min, 8.0℃ / min, 8.5℃ / min, 9.0℃ / min, 9.5℃ / min or 10.0℃ / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some optional instances, the target temperature for the first annealing treatment is 500~600℃, for example, it can be 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃ or 600℃, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0022] In some optional instances, the holding time for the first annealing treatment is 60 to 80 minutes, for example, 60 minutes, 62 minutes, 64 minutes, 66 minutes, 68 minutes, 70 minutes, 72 minutes, 74 minutes, 76 minutes, 78 minutes or 80 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0023] As a preferred technical solution of the present invention, the round wire after the first annealing treatment is straightened in a multi-roller straightening device.

[0024] In some optional instances, the traveling speed of the first annealed round wire in the multi-roller straightening device is 30 to 50 m / min, for example, it can be 30 m / min, 32 m / min, 34 m / min, 36 m / min, 38 m / min, 40 m / min, 42 m / min, 44 m / min, 46 m / min, 48 m / min or 50 m / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] In some optional instances, the tension of the first annealed round wire in the multi-roller straightening device is 50~100N, for example, it can be 50N, 55N, 60N, 65N, 70N, 75N, 80N, 85N, 90N, 95N or 100N, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0026] As a preferred embodiment of the present invention, the axes of the top roller and the bottom roller are horizontal and perpendicular to the direction of travel of the circular line.

[0027] In some alternative examples, the axis of the support roller is vertical and perpendicular to the direction of travel of the circular line.

[0028] In some optional examples, the chemical composition of the top roller, by weight percentage, includes: C 1.3~1.5%, W 4~5%, Mo 4.5~5.5%, V 1.8~2.2%, Co 7~8%, Cr 7~9%, Nb 0.1~0.3%, Ni 0.5~1.5%, with the balance being Fe, wherein the C content can be 1.3%, 1.32%, 1.34%, 1.36%, 1.38%, 1.4%, 1.42%, 1.44%, 1.46%, 1.48% or 1.5%, the W content can be 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5.0%, the Mo content can be 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4% or 5.5%, the V content can be 1.8%, 1.85%, 1.9%, 1.95%, 2.0%, 2.05%, 2.1%, 2.15% or 2.2%, and the Co content can be 7.0%. The Cr content can be 7.0%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, or 8.0%, and the Nb content can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.24%, 0.26%, 0.28%, or 0.3%. The Ni content can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0029] The annular protrusions on the surface of the top roll need to instantly complete the large deformation and high-precision plastic forming of the preheated circular wire in a single rolling process, completely transforming the circular cross-section into a complex cross-section with a specific U-shaped groove. This process means that the protruding part of the top roll needs to continuously withstand extremely high local contact stress, severe friction and wear, and high temperature caused by deformation heat and friction heat during continuous operation. Traditional multi-pass rolling processes distribute the total deformation and corresponding load across multiple passes and rolls, resulting in a relatively light load on each roll and allowing for intermittent cooling. In contrast, one-pass forming processes concentrate all forming loads onto a single, continuous top roll. This places higher demands on the top roll material's high-temperature strength, wear resistance, impact toughness, and overall dimensional stability. If the top roll undergoes plastic deformation due to insufficient strength or hardness during a single continuous rolling process, the geometry of its annular protrusions will change, leading to uneven groove depths and angle changes, directly causing batch scrapping. If the top roll's wear resistance is insufficient, the annular protrusions will change size due to wear, resulting in unstable groove dimensions and product inconsistency. If the top roll lacks toughness, the edges of the annular protrusions are prone to chipping or peeling under high-speed continuous impact loads, damaging the rolls and causing scratches on the round surface.

[0030] To meet the high performance requirements of the top roll in a single rolling process, this invention redesigns the chemical composition of the top roll. By adding carbon, tungsten, molybdenum, and vanadium, the top roll is endowed with extremely high strength, hardness, and wear resistance. Cobalt is added to improve thermal stability and thermal conductivity, and to enhance the secondary hardening effect. Cobalt and chromium are added to ensure the corrosion resistance and hardenability of the top roll. Trace amounts of niobium and nickel are added to refine the grains, improve toughness, and ensure safety and reliability.

[0031] This invention controls the carbon (C) content to 1.3-1.5%. Carbon is the most important solid solution strengthening and precipitation strengthening element in steel. It forms a solid solution with iron and forms a large number of hard, fine carbides with other alloying elements. Within the content range specified by this invention, a high-strength martensitic matrix can be obtained after heat treatment, providing sufficient carbon source for the subsequent formation of various alloy carbides. If the carbon content is less than 1.3%, the hardness of the steel matrix will be insufficient. Under the high pressure of rolling the round wire, the annular protrusions on the surface of the top roll are prone to collapse or wear, resulting in shallower groove depth and distorted shape, which cannot guarantee the long-term stability of the groove dimensions. Conversely, if the carbon content exceeds 1.5%, although the hardness will be further improved, the brittleness of the material will increase significantly and the toughness will decrease. Under the continuous impact rolling load, the edges of the annular protrusions on the surface of the top roll are prone to chipping or microcracks, which will not only leave scratches on the surface of the round wire, but may even lead to the scrapping of the entire top roll.

[0032] Tungsten, molybdenum, and vanadium can all form very stable, fine, and dispersed carbides (W₂C, Mo₂C, VC). These carbides have extremely high hardness, hindering the movement of metal dislocations during rolling, thus significantly improving the yield strength and wear resistance of steel. Furthermore, carbides significantly improve the red hardness of the top roll, ensuring it maintains high hardness even at high temperatures. During continuous rolling of round wire, the roll surface temperature inevitably rises. Tungsten and molybdenum carbides are very stable at high temperatures, effectively suppressing steel softening and tempering, ensuring the top roll maintains high dimensional accuracy throughout long-term production. Vanadium carbides are particularly fine, strongly inhibiting austenite grain growth during heat treatment, thus refining the grain size of the final microstructure, improving both the strength and toughness of the top roll.

[0033] Cobalt is soluble in the matrix but does not form carbides. Its main function is to increase the melting point of steel and slow down the diffusion rate of alloying elements in austenite. During heat treatment, it can increase the quenching temperature without overheating, allowing more alloying carbides to dissolve into the matrix, thus achieving a higher secondary hardening effect during tempering. In addition, cobalt can improve the thermal conductivity of steel, which helps to quickly transfer the heat generated by rolling friction from the roll surface to the roll core and dissipate it, reducing the working temperature of the roll surface. This helps maintain the red hardness of the top roll and prevents the formation of thermal fatigue cracks.

[0034] The main functions of chromium are twofold: firstly, to improve the hardenability of steel, ensuring uniform cross-sectional properties of large-size top rolls; and secondly, to provide excellent oxidation and corrosion resistance. During the rolling process, lubricant can decompose locally at high temperatures, producing corrosive substances. Chromium can form a dense oxide film on the steel surface, providing protection.

[0035] Niobium is a strong carbonitride forming element. Its role is to form extremely stable Nb(C,N) particles, which strongly pin the grain boundaries during austenitization heating, effectively preventing austenite grain growth and obtaining fine original austenite grains. The fine grain structure can simultaneously improve the strength and toughness of the top roller.

[0036] Nickel does not form carbides in steel; it mainly dissolves in the ferrite matrix, which can significantly improve the toughness of steel, especially its low-temperature toughness, and has a certain solid solution strengthening effect. The addition of nickel can partially offset the brittleness caused by high carbon and high alloy, so that the top roller has ultra-high hardness and wear resistance while still having sufficient toughness to resist impact loads and avoid breakage in unexpected situations.

[0037] As a preferred technical solution of the present invention, the straightened round wire is preheated to 180~200℃ and then fed into the four-roll mill. For example, the temperature can be 180℃, 182℃, 184℃, 186℃, 188℃, 190℃, 192℃, 194℃, 196℃, 198℃ or 200℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] While pure copper possesses good plasticity at room temperature, the drastic deformation from round wire to U-shaped groove requires extremely high rolling forces. This not only increases equipment load and accelerates roll wear but also easily leads to incomplete filling or internal stress concentration due to insufficient metal flow. Therefore, this invention preheats the round wire to 180-200°C before performing a one-time composite rolling process. This preheating improves the plastic deformation capacity of pure copper, allowing the pure copper round wire to achieve more uniform and smooth plastic flow under relatively lower rolling forces. This ensures that the round wire fully fills the cavity formed by the top roll, bottom roll, and support roll, especially at the root of the groove and the corners of the sidewalls, ultimately obtaining a groove semi-finished product with a complete shape and precise dimensions.

[0039] If the preheating temperature is too low, the softening effect on the round wire will be insufficient, the deformation resistance will be high, resulting in incomplete forming and increased roll load. If the preheating temperature is too high, it will cause severe oxidation of the round wire surface, forming oxide scale and deteriorating the surface quality. At the same time, the tendency for grain growth will be intensified, resulting in coarse structure and decreased performance of the final product.

[0040] In some optional instances, the travel speed of the preheated round wire in the four-high mill is 30 to 40 m / min, for example, it can be 30 m / min, 31 m / min, 32 m / min, 33 m / min, 34 m / min, 35 m / min, 36 m / min, 37 m / min, 38 m / min, 39 m / min or 40 m / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0041] In some optional instances, the tension of the preheated round wire in the four-roll mill is 200~300N, for example, 200N, 210N, 220N, 230N, 240N, 250N, 260N, 270N, 280N, 290N or 300N, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0042] In some optional instances, the fillet radius of the rounded trapezoidal section of the annular protrusion is 0.3 to 0.5 mm, for example, it can be 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm or 0.5 mm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0043] In some optional instances, the base angle of the rounded trapezoidal cross section of the annular protrusion is 60 to 70°, for example, it can be 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69° or 70°, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] In some alternative instances, the ratio of the height of the annular protrusion to the depth of the finished groove line is 1:(1.1~1.2), for example, it can be 1:1.1, 1:1.11, 1:1.12, 1:1.13, 1:1.14, 1:1.15, 1:1.16, 1:1.17, 1:1.18, 1:1.19 or 1:1.2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0045] To achieve one-step rolling, this invention redesigns the shape of the annular protrusion on the top roll. The cross-sectional shape of the annular protrusion is a rounded trapezoid. The trapezoidal structure itself facilitates the gradual deformation of the metal, and its inclined sidewalls guide the compressed circular wire to flow more smoothly to the sides and forward, significantly reducing deformation resistance compared to a vertical wall. The rounded corner structure is located at the junction of the top surface of the trapezoid and the sidewall, where stress concentration is most severe. If this corner were sharp during rolling, it would generate extremely high stress, easily causing cracking in that area due to stress concentration, and also easily generating micro-cracks at the root of the groove in the forming groove. By designing a rounded corner with a radius of 0.3~0.5mm, a smooth stress distribution area is formed at the junction of the top surface of the trapezoid and the sidewall, effectively protecting the roll and preventing cracks from appearing at the root of the groove.

[0046] As a preferred technical solution of the present invention, the traveling speed of the grooved wire in the drawing machine is 40~50m / min, for example, it can be 40m / min, 41m / min, 42m / min, 43m / min, 44m / min, 45m / min, 46m / min, 47m / min, 48m / min, 49m / min or 50m / min, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0047] In some optional instances, the drawing process consists of three passes, wherein the deformation rate of the first pass is 10-12%, for example, 10%, 10.2%, 10.4%, 10.6%, 10.8%, 11%, 11.2%, 11.4%, 11.6%, 11.8%, or 12%; the deformation rate of the intermediate passes is 8-10%, for example, 8.0%, 8.2%, 8.4%, 8.6%, 8.8%, 9.0%, 9.2%, 9.4%, 9.6%, 9.8%, or 10.0%; and the deformation rate of the final pass is 3-5%, for example, 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, 4.0%, 4.2%, 4.4%, 4.6%, 4.8%, or 5.0%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0048] This invention employs a three-pass drawing process. The first pass is primarily used for size reduction and shape regularization. The main shape of the semi-finished groove line obtained by rolling is already formed, but there are slight dimensional fluctuations and elastic recovery effects. This invention sets the deformation rate of the first pass at 10-12%, which can effectively eliminate the microstructure inhomogeneity present during the rolling process by utilizing sufficiently large plastic deformation, making the groove line outline clearer. However, the deformation rate of the first pass cannot be too high. This is to avoid work hardening due to excessive deformation in a single pass, which would make the material too hard and brittle, not only increasing the drawing force and accelerating die wear, but also making subsequent deformation passes difficult or even causing surface cracks.

[0049] The deformation rate in intermediate passes is reduced to 8-10%. Its function is to facilitate a smooth dimensional transition and work hardening based on the relatively regular structure formed after the first drawing pass. This requires both further reducing the groove dimensions to gradually approach the finished product size requirements and ensuring a sufficiently smooth deformation process. Compared to the first pass, the lower deformation rate in intermediate passes helps to achieve more uniform material flow and facilitates the redistribution of internal stress, thereby reducing the risk of groove bending or torsion due to uneven deformation.

[0050] The deformation rate of the final pass is further reduced to 3-5%. At this point, the size of the groove is very close to the size requirements of the final product. Its function is to make precise adjustments to the groove size at the micron level and eliminate the small errors left over from the first two passes.

[0051] In some optional instances, the drawing process uses a die angle of 10 to 12°, for example, 10°, 10.2°, 10.4°, 10.6°, 10.8°, 11°, 11.2°, 11.4°, 11.6°, 11.8° or 12°, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0052] In some alternative instances, the sizing strip length of the drawing die is 0.5 to 0.8 mm, for example, it can be 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm or 0.8 mm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0053] As a preferred technical solution of the present invention, the first lubricant is prepared before use by mixing the concentrate with deionized water at a volume ratio of 1:(15~25), for example, it can be 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24 or 1:25, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0054] In some alternative instances, the second lubricant is prepared before use by mixing a concentrate with deionized water at a volume ratio of 1:(5~10), for example, 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5, 1:8.0, 1:8.5, 1:9.0, 1:9.5 or 1:10.0, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0055] The large contact area and high pressure between the rolls and the round wire, coupled with the large deformation and high rolling speed, generate significant deformation and frictional heat. Furthermore, the preheated round wire, reaching 180-200°C, further exacerbates the interface temperature between the rolls and the wire. This invention addresses this by uniformly applying a lubricant to the surface of the round wire before rolling. This lubricant serves to cool and dissipate heat, preventing damage to the rolls and wire due to overheating or deterioration of their microstructure. The lubricant is prepared by mixing a concentrated solution of lubricant and deionized water at a volume ratio of 1:(15-25). The higher proportion of deionized water fully utilizes water's high specific heat capacity and latent heat of vaporization, achieving rapid cooling. Additionally, the lower viscosity and better fluidity of the lubricant allow for faster penetration and coverage of the contact area between the rolls and the wire, ensuring the continuity of the lubricating film.

[0056] During the drawing stage of the grooved wire, the concentration of the lubricant is significantly increased, with the concentrate and deionized water prepared at a volume ratio of 1:(5~10). This is because the drawing process differs from the rolling process. Drawing involves reducing and sizing the pre-formed grooved wire using a die, which is a finishing process. At this stage, the contact between the grooved wire and the die is line contact, resulting in extremely concentrated pressure per unit area. Furthermore, the material has already undergone a certain degree of work hardening due to previous processing. Therefore, the lubricant in the drawing process must possess extremely excellent extreme pressure anti-wear properties and film-forming ability. A higher proportion of concentrate ensures that under extremely high local pressure, the active ingredients in the lubricant effectively decompose and react with the metal surface to form a robust chemical reaction film. This film prevents direct contact between the die and the grooved wire surface under high pressure, avoiding scratches and roughening, thereby ensuring the surface smoothness and dimensional accuracy of the grooved wire. Meanwhile, the heat generated during the drawing process is relatively less than that during rolling, and the requirements for cooling are relatively lower. Therefore, the present invention uses a higher concentration of lubricant during the drawing process in order to provide better boundary lubrication and extreme pressure lubrication capabilities, protect the die, and obtain a high-quality finished groove surface.

[0057] In some optional examples, the concentrate includes synthetic ester base oil, extreme pressure anti-wear additives, friction modifiers, antioxidants, emulsifiers, and corrosion inhibitors.

[0058] In some optional examples, the extreme pressure anti-wear additive includes sulfurized olefins, triphenyl thiophosphate, and tributyl phosphate.

[0059] In some optional examples, the friction modifier includes molybdenum dialkyl dithiocarbamate, glyceryl monooleate, and oleic acid.

[0060] In some alternative examples, the antioxidants include disodium ethylenediaminetetraacetate and L-ascorbic acid.

[0061] As a preferred embodiment of the present invention, the mass ratio of sulfurized olefin, triphenyl thiophosphate, and tributyl phosphate in the extreme pressure anti-wear additive is 1:(0.5~0.6):(0.3~0.4), for example, it can be 1:0.5:0.3, 1:0.51:0.31, 1:0.52:0.32, 1:0.53:0.33, 1:0.54:0.34, 1:0.55:0.35, 1:0.56:0.36, 1:0.57:0.37, 1:0.58:0.38, 1:0.59:0.39, or 1:0.6:0.4, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0062] As the main extreme pressure component in lubricants, sulfurized olefins play a role in chemically reacting with metal surfaces at high-temperature and high-pressure friction interfaces to generate a solid lubricating film mainly composed of iron sulfide. This film has low shear strength and can effectively isolate the direct contact between the roll and the surface of the round wire, as well as the die and the surface of the grooved wire, preventing adhesion or scratches under high loads.

[0063] However, films formed from single sulfurized olefins are brittle and the reaction is too vigorous. Therefore, this invention incorporates triphenyl thiophosphate, which possesses extreme pressure and anti-wear properties. The phosphorus element in its molecule can react with metals at high temperatures to form compounds such as iron phosphate. The resulting film is softer, tougher, and has better melt spreadability compared to a simple sulfide film. When sulfurized olefins and triphenyl thiophosphate are compounded in a specific ratio, the chemical reaction between sulfur and phosphorus is optimized, forming a sulfur-phosphorus coexisting composite protective film on the metal surface. This film possesses both high load-bearing capacity and good toughness, allowing it to withstand intense plastic deformation more smoothly. This invention further incorporates tributyl phosphate. Tributyl phosphate has strong molecular polarity, excellent permeability and oiling properties, and can preferentially adsorb onto the metal surface. Even before the pressure reaches the critical point that triggers a vigorous reaction between sulfur and phosphorus, it can provide preliminary lubrication and friction reduction effects.

[0064] At the friction interface, tributyl phosphate initially provides adsorption lubrication, offering preliminary lubrication and friction reduction. As pressure and temperature increase, triphenyl thiophosphate and sulfurized olefins react to form a tough chemical reaction film. If the amount of sulfurized olefins is too high, the reaction film becomes too brittle and easily peels off, even causing excessive corrosion to the round wire. If the amount of triphenyl thiophosphate is too low, the resulting composite film layer lacks toughness and its resistance to impact loads decreases. If the amount of tributyl phosphate is too high, its excessive oiliness will affect the strength of the extreme pressure film formation and produce excessive residues at high temperatures.

[0065] In some optional examples, the mass ratio of molybdenum dialkyl dithiocarbamate, glyceryl monooleate, and oleic acid in the friction modifier is 1:(1.5~2):(0.5~0.7), for example, it can be 1:1.5:0.5, 1:1.55:0.52, 1:1.6:0.54, 1:1.65:0.56, 1:1.7:0.58, 1:1.75:0.6, 1:1.8:0.62, 1:1.85:0.64, 1:1.9:0.66, 1:1.95:0.68, or 1:2:0.7, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0066] Molybdenum dialkyldithiocarbamate can decompose under moderate temperature and pressure conditions at the friction interface, reacting to generate molybdenum disulfide microparticles with a layered structure. These microparticles can effectively adhere to the surface of round or grooved lines, forming a solid lubricating film with extremely low shear strength. This transforms the sliding friction between the contact surface of the round line and the roll or between the grooved line and the die into the internal molecular layer slippage between the MoS2 layers, thereby significantly reducing the coefficient of friction.

[0067] However, the film formed solely by molybdenum compounds results in discontinuous and weak coverage in certain areas of the surface. To address this, the present invention incorporates glyceryl monooleate. As a highly polar ester compound, glyceryl monooleate can firmly adsorb onto the surface of the circular wire through its polar ends, forming a dense, oriented adsorption film. This adsorption film not only possesses a certain friction-reducing effect but, more importantly, provides an ideal substrate for the molybdenum disulfide particles, the decomposition product of molybdenum dialkyldithiocarbamate. This allows for more uniform and stable spreading and adhesion to the surface of the circular or grooved wires, thereby enhancing the continuity and durability of the MoS2 lubricating film. Oleic acid, as a monounsaturated fatty acid, also has a strong surface adsorption capacity. Its molecules can form an adsorption layer on the surface of the circular or grooved wires, improving the spreadability and penetration of the lubricant on these surfaces and ensuring that the lubricant can quickly reach and cover all contact interfaces.

[0068] Glyceryl monooleate first forms a robust adsorption substrate on the surface of the circular or grooved lines. Molybdenum dialkyldithiocarbamate decomposes on the adsorption substrate to generate an ultra-low friction MoS2 film, which plays a major role in reducing friction. Oleic acid enhances the spreadability and rapid protective ability of the lubricant. This invention specifically limits the mass ratio of molybdenum dialkyldithiocarbamate, glyceryl monooleate, and oleic acid to 1:(1.5~2):(0.5~0.7). If the amount of molybdenum dialkyldithiocarbamate is too low, the lubrication and friction-reducing effect will be insufficient. If the amount of molybdenum dialkyldithiocarbamate is too high, its decomposition product MoS2 will agglomerate into larger agglomerates, increasing the frictional resistance at the contact surface and affecting the surface cleanliness of the finished grooved lines. If the amount of glyceryl monooleate is too low, the formed adsorption substrate will be incomplete, and the MoS2 film cannot adhere effectively. If the amount of glyceryl monooleate is too high, the lubricant will become too viscous, affecting its flowability.

[0069] In some alternative examples, the mass ratio of disodium ethylenediaminetetraacetate and L-ascorbic acid in the antioxidant is 1:(0.3~0.5), for example, it can be 1:0.3, 1:0.32, 1:0.34, 1:0.36, 1:0.38, 1:0.4, 1:0.42, 1:0.44, 1:0.46, 1:0.48 or 1:0.5, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0070] Disodium EDTA is a metal chelating agent that effectively captures and firmly binds dissolved metal ions present in lubricants. These ions mainly originate from equipment wear (such as iron ions) or working materials (copper ions). These metal ions are strong catalysts for the oxidation reaction of lubricants, significantly promoting the oxidative degradation of base oils and additives. By adding disodium EDTA to chelate and fix these metal ions, the oxidation reaction pathway catalyzed by metal ions is fundamentally interrupted.

[0071] However, the oxidation process of lubricants also includes free radical chain reactions directly triggered by factors such as heat and oxygen, a process that is difficult to completely inhibit using metal chelating agents alone. Therefore, this invention incorporates L-ascorbic acid, a free radical scavenger whose molecules are easily oxidized. L-ascorbic acid preferentially reacts with reactive intermediates such as peroxide free radicals already generated in the lubricant, thereby interrupting the propagation of the chain reaction and preventing abnormal increases in lubricant viscosity, the formation of acidic substances, and the formation of deposits and sludge.

[0072] As a preferred embodiment of the present invention, the concentrate, in 100 parts by weight, comprises the following components in parts by weight:

[0073] 65-75 parts of synthetic ester base oil;

[0074] 10-12 parts of extreme pressure anti-wear additive;

[0075] Friction modifier 3-5 parts;

[0076] 1-2 parts antioxidant;

[0077] 10-15 parts emulsifier;

[0078] 0.5 to 1 part corrosion inhibitor.

[0079] In some optional examples, the emulsifier is an alkylphenol polyoxyethylene ether.

[0080] In some optional instances, the corrosion inhibitor is benzotriazole.

[0081] The synthetic ester base oil can be in the following proportions by weight: 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, or 75 parts; the extreme pressure anti-wear additive can be in the following proportions by weight: 10 parts, 10.2 parts, 10.4 parts, 10.6 parts, 10.8 parts, 11 parts, 11.2 parts, 11.4 parts, 11.6 parts, 11.8 parts, or 12 parts; the friction modifier can be in the following proportions by weight: 3.0 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4.0 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, or 5.0 parts; and the antioxidant can be in the following proportions by weight: 1.0 part. 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2.0 parts by weight; the emulsifier may be 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, or 15 parts by weight; the corrosion inhibitor may be 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, or 1.0 parts by weight, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0082] Synthetic ester base oil, as the main component, possesses excellent lubricity and viscosity-temperature characteristics. It can form an oil film on the metal surface, directly reducing friction between the tool and the workpiece. Its main functions are to provide basic lubrication, transmit pressure, and act as a carrier. This invention specifically limits the addition amount of synthetic ester base oil to 65-75 parts. If the amount is less than 65 parts, the oil film strength will be insufficient, unable to effectively withstand the high pressure during rolling, and the overall life and stability of the lubricant will also decrease. If the amount is more than 75 parts, the proportion of extreme pressure anti-wear additives and friction modifiers will be relatively low, failing to effectively prevent adhesion and wear.

[0083] Extreme pressure anti-wear additives undergo a chemical reaction under high temperature and pressure to form a protective film on the surface of the workpiece, preventing welding and scratches caused by direct contact between the tool and the workpiece. This invention specifically limits the dosage of extreme pressure anti-wear additives to 10-12 parts. If the dosage is less than 10 parts, the protective film formed will be insufficient in strength and will fail during high-load rolling and drawing. If the dosage is more than 12 parts, it will not only lead to increased production costs, but excessive active sulfur and phosphorus substances will also cause excessive chemical corrosion to copper workpieces, thereby damaging the surface quality of the groove lines.

[0084] Friction modifiers effectively reduce the coefficient of friction at the contact interface by forming an adsorption film on the metal surface and undergoing a chemical reaction to generate a surface layer with low shear strength. This reduces frictional resistance and energy consumption during processing and protects the tool and workpiece surfaces from damage. This invention specifically limits the dosage of the friction modifier to 3-5 parts. If the dosage is less than 3 parts, the formed lubricating film is incomplete and lacks strength, failing to effectively reduce the coefficient of friction during intense plastic deformation, leading to a rapid increase in temperature and a decrease in workpiece surface quality. If the dosage is greater than 5 parts, the excessive decomposition products of molybdenum dialkyldithiocarbamate (MoS2) will agglomerate into larger agglomerates, increasing frictional resistance at the contact surface. Simultaneously, the accumulation of decomposition products will contaminate the workpiece surface, affecting the surface cleanliness of the finished groove lines.

[0085] Emulsifiers ensure that oleophobic base oils and additives form a stable and uniform emulsion in deionized water. Insufficient emulsion dosage leads to emulsion instability, oil-water separation, and a significant reduction in lubrication and cooling effects; excessive dosage results in an overly viscous emulsion, affecting its fluidity and cooling performance, and increasing costs. Antioxidants inhibit the oxidative deterioration of lubricants under high temperatures and mechanical shear by chelating metal ions and capturing free radicals, thus extending service life. Corrosion inhibitors are particularly effective on copper and its alloys, adsorbing onto the copper surface to form a protective film, preventing moisture and active ingredients in the lubricant from corroding the copper tubing.

[0086] As a preferred embodiment of the present invention, the heating rate of the second annealing treatment is 5~10℃ / min, for example, it can be 5.0℃ / min, 5.5℃ / min, 6.0℃ / min, 6.5℃ / min, 7.0℃ / min, 7.5℃ / min, 8.0℃ / min, 8.5℃ / min, 9.0℃ / min, 9.5℃ / min or 10.0℃ / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0087] In some optional instances, the target temperature for the second annealing treatment is 450~500°C, for example, 450°C, 455°C, 460°C, 465°C, 470°C, 475°C, 480°C, 485°C, 490°C, 495°C or 500°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0088] In some optional instances, the holding time for the second annealing treatment is 100 to 120 minutes, for example, 100 minutes, 102 minutes, 104 minutes, 106 minutes, 108 minutes, 110 minutes, 112 minutes, 114 minutes, 116 minutes, 118 minutes or 120 minutes, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0089] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0090] The preparation method provided by this invention uses a special irregular structure roll and a special lubricant to achieve one-time composite rolling, eliminating the need for the lengthy path of multiple rolling passes or sequential deformation of drawing dies required by traditional processes, and realizing efficient and high-precision one-time forming from round line to U-shaped groove line. Attached Figure Description

[0091] Figure 1 The process flow diagrams for the short-process rolling and drawing of irregular copper channel wires provided in Embodiments 1-5 of the present invention are shown below.

[0092] Figure 2 This is a schematic diagram of the structure of the four-roll assembly of the four-roll mill provided in Embodiments 1-5 of the present invention.

[0093] Explanation of reference numerals in the attached diagram: 1. Top roller; 2. Annular protrusion; 3. Support roller; 4. Bottom roller. Detailed Implementation

[0094] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0095] Example 1

[0096] This embodiment provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire, such as... Figure 1 As shown, the rolling and drawing preparation method specifically includes the following steps:

[0097] (1) Under a protective atmosphere composed of nitrogen and hydrogen (hydrogen volume fraction of 5%), pure copper round wire with a diameter of 8 mm (copper content not less than 99.90%) is heated to 500°C at a heating rate of 5°C / min and held for 80 min. Then, it is cooled to room temperature in the furnace to complete the first annealing. The round wire after the first annealing is sent to a multi-roller straightening device for straightening. The traveling speed of the round wire in the multi-roller straightening device is 30 m / min and the tension is 100 N.

[0098] (2) Mix the concentrate and deionized water at a volume ratio of 1:15 to obtain the first lubricant. Coat the straightened round wire with the first lubricant. After preheating the round wire to 180°C, send it into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove. The traveling speed of the round wire in the four-roll mill is 30m / min and the tension is 300N.

[0099] like Figure 2 As shown, the four-high rolling mill includes a top roll 1 located at the top of the circular line, a bottom roll 4 located at the bottom of the circular line, and support rolls 3 located on both sides of the circular line. The axes of the top roll 1 and the bottom roll 4 are horizontal and perpendicular to the direction of travel of the circular line. The axes of the support rolls 3 on both sides of the circular line are vertical and perpendicular to the direction of travel of the circular line. During the rolling process, the bottom roll 4 is used to form the bottom surface of the groove, and the support rolls 3 on both sides are used to form the sidewalls of the groove. The surface of the top roll 1 is provided with an annular protrusion 2 with a rounded trapezoidal cross-section. The annular protrusion 2 is used to form the groove of the groove. The radius of the rounded corner of the annular protrusion 2 is 0.3 mm, the base angle is 60°, and the ratio of the height of the annular protrusion 2 to the depth of the finished groove is 1:1.1.

[0100] The chemical composition of top roller 1, by weight percentage, includes: C 1.3%, W 5%, Mo 4.5%, V 2.2%, Co 7%, Cr 9%, Nb 0.1%, Ni 0.5%, with the balance being Fe;

[0101] The bottom roller 4 is made of cold work die steel D2 (Cr12Mo1V1), and the support roller 3 is made of high speed steel H13 (4Cr5MoSiV1).

[0102] (3) The concentrate and deionized water are mixed evenly at a volume ratio of 1:5 to obtain the second lubricant. The second lubricant is applied to the surface of the rolled groove line, and the groove line is drawn. The drawing speed of the groove line in the drawing machine is 40m / min. The groove line is drawn in 3 passes. The deformation rate of the first pass is 10%, the deformation rate of the middle pass is 8%, and the deformation rate of the last pass is 3%. The die angle of the drawing die is 10° and the sizing band length of the die is 0.5mm.

[0103] The concentrate used in steps (2) and (3) has the same composition and ratio. Based on 100 parts by weight of the concentrate, it includes the following components in parts by weight:

[0104] 65 parts of trimethylolpropane oleate;

[0105] 12 parts of extreme pressure anti-wear additive;

[0106] 5 parts friction modifier;

[0107] Two parts antioxidant;

[0108] 15 parts of alkylphenol polyoxyethylene ether;

[0109] Benzotriazole 1 part;

[0110] The extreme pressure anti-wear additive is composed of sulfurized olefins, triphenyl thiophosphate and tributyl phosphate in a mass ratio of 1:0.5:0.3; the friction modifier is composed of molybdenum dialkyl dithiocarbamate, glyceryl monooleate and oleic acid in a mass ratio of 1:1.5:0.5; and the antioxidant is composed of disodium ethylenediaminetetraacetate and L-ascorbic acid in a mass ratio of 1:0.3.

[0111] (4) After the drawing is completed, the groove line is subjected to a second annealing treatment. It is heated to 450°C at a heating rate of 5°C / min and held for 120 min. After cooling to room temperature in the furnace, the second annealing treatment is completed. Finally, the groove line after the second annealing treatment is cleaned by ultrasonic cleaning to obtain the finished groove line.

[0112] Example 2

[0113] This embodiment provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire, such as... Figure 1 As shown, the rolling and drawing preparation method specifically includes the following steps:

[0114] (1) Under a protective atmosphere composed of nitrogen and hydrogen (volume fraction of hydrogen is 6%), pure copper round wire with a diameter of 8.5 mm (copper content not less than 99.90%) is heated to 520°C at a heating rate of 6°C / min and held for 75 min. Then, it is cooled to room temperature in the furnace to complete the first annealing. The round wire after the first annealing is sent to a multi-roller straightening device for straightening. The traveling speed of the round wire in the multi-roller straightening device is 35 m / min and the tension is 80 N.

[0115] (2) Mix the concentrate and deionized water at a volume ratio of 1:18 to obtain the first lubricant. Coat the straightened round wire with the first lubricant. After preheating the round wire to 185°C, send it into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove. The traveling speed of the round wire in the four-roll mill is 32m / min and the tension is 280N.

[0116] like Figure 2 As shown, the four-high rolling mill includes a top roll 1 located at the top of the circular line, a bottom roll 4 located at the bottom of the circular line, and support rolls 3 located on both sides of the circular line. The axes of the top roll 1 and the bottom roll 4 are horizontal and perpendicular to the direction of travel of the circular line. The axes of the support rolls 3 on both sides of the circular line are vertical and perpendicular to the direction of travel of the circular line. During the rolling process, the bottom roll 4 is used to form the bottom surface of the groove, and the support rolls 3 on both sides are used to form the sidewalls of the groove. The surface of the top roll 1 is provided with an annular protrusion 2 with a rounded trapezoidal cross-section. The annular protrusion 2 is used to form the groove of the groove. The radius of the rounded corner of the annular protrusion 2 is 0.35 mm, the base angle is 62°, and the ratio of the height of the annular protrusion 2 to the depth of the finished groove is 1:1.12.

[0117] The chemical composition of top roller 1, by weight percentage, includes: C 1.35%, W 4.8%, Mo 4.8%, V 2.1%, Co 7.2%, Cr 8.5%, Nb 0.15%, Ni 0.7%, with the balance being Fe;

[0118] The bottom roller 4 is made of cold work die steel D2 (Cr12Mo1V1), and the support roller 3 is made of high speed steel H13 (4Cr5MoSiV1).

[0119] (3) The concentrate and deionized water are mixed evenly at a volume ratio of 1:6 to obtain the second lubricant. The second lubricant is applied to the surface of the rolled groove line, and the groove line is drawn. The drawing speed of the groove line in the drawing machine is 42m / min. The groove line is drawn in 3 passes. The deformation rate of the first pass is 11%, the deformation rate of the middle pass is 8%, and the deformation rate of the last pass is 3%. The die angle of the drawing die is 11° and the sizing band length of the die is 0.6mm.

[0120] The concentrate used in steps (2) and (3) has the same composition and ratio. Based on 100 parts by weight of the concentrate, it includes the following components in parts by weight:

[0121] 68 parts of trimethylolpropane oleate;

[0122] 12 parts of extreme pressure anti-wear additive;

[0123] 4 parts friction modifier;

[0124] 1.5 parts antioxidant;

[0125] 14 parts of alkylphenol polyoxyethylene ether;

[0126] Benzotriazole 0.5 parts;

[0127] The extreme pressure anti-wear additive is composed of sulfurized olefins, triphenyl thiophosphate and tributyl phosphate in a mass ratio of 1:0.52:0.32; the friction modifier is composed of molybdenum dialkyl dithiocarbamate, glyceryl monooleate and oleic acid in a mass ratio of 1:1.6:0.55; and the antioxidant is composed of disodium ethylenediaminetetraacetate and L-ascorbic acid in a mass ratio of 1:0.35.

[0128] (4) After the drawing is completed, the grooved line is subjected to a second annealing treatment. It is heated to 460°C at a heating rate of 6°C / min and held for 115 minutes. After cooling to room temperature in the furnace, the second annealing treatment is completed. Finally, the grooved line after the second annealing treatment is cleaned by ultrasonic cleaning to obtain the finished grooved line.

[0129] Example 3

[0130] This embodiment provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire, such as... Figure 1 As shown, the rolling and drawing preparation method specifically includes the following steps:

[0131] (1) Under a protective atmosphere composed of nitrogen and hydrogen (the volume fraction of hydrogen is 7%), a pure copper round wire with a diameter of 9 mm (copper content not less than 99.90%) is heated to 550°C at a heating rate of 7°C / min and held for 70 min. Then, it is cooled to room temperature in the furnace to complete the first annealing. The round wire after the first annealing is sent to a multi-roller straightening device for straightening. The traveling speed of the round wire in the multi-roller straightening device is 40 m / min and the tension is 70 N.

[0132] (2) Mix the concentrate and deionized water at a volume ratio of 1:20 to obtain the first lubricant. Coat the straightened round wire with the first lubricant. After preheating the round wire to 190°C, send it into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove. The traveling speed of the round wire in the four-roll mill is 35m / min and the tension is 250N.

[0133] like Figure 2 As shown, the four-high rolling mill includes a top roll 1 located at the top of the circular line, a bottom roll 4 located at the bottom of the circular line, and support rolls 3 located on both sides of the circular line. The axes of the top roll 1 and the bottom roll 4 are horizontal and perpendicular to the direction of travel of the circular line. The axes of the support rolls 3 on both sides of the circular line are vertical and perpendicular to the direction of travel of the circular line. During the rolling process, the bottom roll 4 is used to form the bottom surface of the groove, and the support rolls 3 on both sides are used to form the sidewalls of the groove. The surface of the top roll 1 is provided with an annular protrusion 2 with a rounded trapezoidal cross-section. The annular protrusion 2 is used to form the groove of the groove. The radius of the rounded corner of the rounded trapezoidal cross-section of the annular protrusion 2 is 0.4 mm, the base angle is 65°, and the ratio of the height of the annular protrusion 2 to the depth of the finished groove is 1:1.15.

[0134] The chemical composition of top roller 1, by weight percentage, includes: C 1.4%, W 4.5%, Mo 5%, V 2%, Co 7.5%, Cr 8%, Nb 0.2%, Ni 1%, with the balance being Fe;

[0135] The bottom roller 4 is made of cold work die steel D2 (Cr12Mo1V1), and the support roller 3 is made of high speed steel H13 (4Cr5MoSiV1).

[0136] (3) The concentrate and deionized water are mixed evenly at a volume ratio of 1:7 to obtain the second lubricant. The second lubricant is applied to the surface of the rolled groove line, and the groove line is drawn. The drawing speed of the groove line in the drawing machine is 45m / min. The groove line is drawn in 3 passes. The deformation rate of the first pass is 11%, the deformation rate of the middle pass is 9%, and the deformation rate of the last pass is 4%. The die angle of the drawing die is 11° and the sizing band length of the die is 0.6mm.

[0137] The concentrate used in steps (2) and (3) has the same composition and ratio. Based on 100 parts by weight of the concentrate, it includes the following components in parts by weight:

[0138] 70 parts of trimethylolpropane oleate;

[0139] 11 parts of extreme pressure anti-wear additive;

[0140] 5 parts friction modifier;

[0141] 1.5 parts antioxidant;

[0142] 12 parts of alkylphenol polyoxyethylene ether;

[0143] Benzotriazole 0.5 parts;

[0144] The extreme pressure anti-wear additive is composed of sulfurized olefins, triphenyl thiophosphate and tributyl phosphate in a mass ratio of 1:0.55:0.35; the friction modifier is composed of molybdenum dialkyl dithiocarbamate, glyceryl monooleate and oleic acid in a mass ratio of 1:1.7:0.6; and the antioxidant is composed of disodium ethylenediaminetetraacetate and L-ascorbic acid in a mass ratio of 1:0.4.

[0145] (4) After the drawing is completed, the grooved line is subjected to a second annealing treatment. It is heated to 470°C at a heating rate of 7°C / min and held for 110 min. After cooling to room temperature in the furnace, the second annealing treatment is completed. Finally, the grooved line after the second annealing treatment is cleaned by ultrasonic cleaning to obtain the finished grooved line.

[0146] Example 4

[0147] This embodiment provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire, such as... Figure 1 As shown, the rolling and drawing preparation method specifically includes the following steps:

[0148] (1) Under a protective atmosphere composed of nitrogen and hydrogen (volume fraction of hydrogen is 8%), pure copper round wire with a diameter of 9.5 mm (copper content not less than 99.90%) is heated to 580°C at a heating rate of 8°C / min and held for 65 min. Then, it is cooled to room temperature in the furnace to complete the first annealing. The round wire after the first annealing is sent to a multi-roller straightening device for straightening. The traveling speed of the round wire in the multi-roller straightening device is 45 m / min and the tension is 60 N.

[0149] (2) The concentrate and deionized water are mixed evenly at a volume ratio of 1:22 to obtain the first lubricant. The first lubricant is coated on the surface of the straightened round wire. The round wire is preheated to 195°C and then sent into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove. The traveling speed of the round wire in the four-roll mill is 38m / min and the tension is 220N.

[0150] like Figure 2 As shown, the four-high rolling mill includes a top roll 1 at the top of the circular line, a bottom roll 4 at the bottom of the circular line, and support rolls 3 on both sides of the circular line. The axes of the top roll 1 and the bottom roll 4 are horizontal and perpendicular to the direction of travel of the circular line. The axes of the support rolls 3 on both sides of the circular line are vertical and perpendicular to the direction of travel of the circular line. During the rolling process, the bottom roll 4 is used to form the bottom surface of the groove, and the support rolls 3 on both sides are used to form the sidewalls of the groove. The surface of the top roll 1 is provided with an annular protrusion 2 with a rounded trapezoidal cross-section. The annular protrusion 2 is used to form the groove of the groove. The radius of the rounded corner of the annular protrusion 2 is 0.45 mm, the base angle is 68°, and the ratio of the height of the annular protrusion 2 to the depth of the finished groove is 1:1.18.

[0151] The chemical composition of top roller 1, by weight percentage, includes: C 1.45%, W 4.2%, Mo 5.5%, V 1.9%, Co 7.8%, Cr 7.5%, Nb 0.25%, Ni 1%, with the balance being Fe;

[0152] The bottom roller 4 is made of cold work die steel D2 (Cr12Mo1V1), and the support roller 3 is made of high speed steel H13 (4Cr5MoSiV1).

[0153] (3) The concentrate and deionized water are mixed evenly at a volume ratio of 1:8 to obtain the second lubricant. The second lubricant is applied to the surface of the rolled groove line, and the groove line is drawn. The drawing speed of the groove line in the drawing machine is 48m / min. The groove line is drawn in 3 passes. The deformation rate of the first pass is 12%, the deformation rate of the middle pass is 9%, and the deformation rate of the last pass is 5%. The die angle of the drawing die is 12° and the sizing band length of the die is 0.7mm.

[0154] The concentrate used in steps (2) and (3) has the same composition and ratio. Based on 100 parts by weight of the concentrate, it includes the following components in parts by weight:

[0155] 72 parts of trimethylolpropane oleate;

[0156] 10 parts of extreme pressure anti-wear additive;

[0157] 3 parts friction modifier;

[0158] Antioxidant 1.2 parts;

[0159] 13 parts of alkylphenol polyoxyethylene ether;

[0160] Benzotriazole 0.8 parts;

[0161] The extreme pressure anti-wear additive is composed of sulfurized olefins, triphenyl thiophosphate and tributyl phosphate in a mass ratio of 1:0.58:0.38; the friction modifier is composed of molybdenum dialkyl dithiocarbamate, glyceryl monooleate and oleic acid in a mass ratio of 1:1.8:0.65; and the antioxidant is composed of disodium ethylenediaminetetraacetate and L-ascorbic acid in a mass ratio of 1:0.45.

[0162] (4) After the drawing is completed, the groove line is subjected to a second annealing treatment. It is heated to 480°C at a heating rate of 8°C / min and held for 105 min. After cooling to room temperature in the furnace, the second annealing treatment is completed. Finally, the groove line after the second annealing treatment is cleaned by ultrasonic cleaning to obtain the finished groove line.

[0163] Example 5

[0164] This embodiment provides a short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire, such as... Figure 1 As shown, the rolling and drawing preparation method specifically includes the following steps:

[0165] (1) Under a protective atmosphere composed of nitrogen and hydrogen (hydrogen volume fraction of 10%), a pure copper round wire with a diameter of 10 mm (copper content not less than 99.90%) is heated to 600 °C at a heating rate of 10 °C / min and held for 60 min, and then cooled to room temperature in the furnace to complete the first annealing; the round wire after the first annealing is sent into a multi-roller straightening device for straightening. The traveling speed of the round wire in the multi-roller straightening device is 50 m / min and the tension is 50 N.

[0166] (2) Mix the concentrate and deionized water at a volume ratio of 1:25 to obtain the first lubricant. Coat the straightened round wire with the first lubricant. After preheating the round wire to 200°C, send it into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove. The traveling speed of the round wire in the four-roll mill is 40m / min and the tension is 200N.

[0167] like Figure 2 As shown, the four-high rolling mill includes a top roll 1 located at the top of the circular line, a bottom roll 4 located at the bottom of the circular line, and support rolls 3 located on both sides of the circular line. The axes of the top roll 1 and the bottom roll 4 are horizontal and perpendicular to the direction of travel of the circular line. The axes of the support rolls 3 on both sides of the circular line are vertical and perpendicular to the direction of travel of the circular line. During the rolling process, the bottom roll 4 is used to form the bottom surface of the groove, and the support rolls 3 on both sides are used to form the sidewalls of the groove. The surface of the top roll 1 is provided with an annular protrusion 2 with a rounded trapezoidal cross-section. The annular protrusion 2 is used to form the groove of the groove. The radius of the rounded corner of the rounded trapezoidal cross-section of the annular protrusion 2 is 0.5 mm, the base angle is 70°, and the ratio of the height of the annular protrusion 2 to the depth of the finished groove is 1:1.2.

[0168] The chemical composition of top roller 1, by weight percentage, includes: C 1.5%, W 4%, Mo 5.5%, V 1.8%, Co 8%, Cr 7%, Nb 0.3%, Ni 1.5%, with the balance being Fe;

[0169] The bottom roller 4 is made of cold work die steel D2 (Cr12Mo1V1), and the support roller 3 is made of high speed steel H13 (4Cr5MoSiV1).

[0170] (3) The concentrate and deionized water are mixed evenly at a volume ratio of 1:10 to obtain the second lubricant. The second lubricant is applied to the surface of the rolled groove line, and the groove line is drawn. The drawing speed of the groove line in the drawing machine is 50m / min. The groove line is drawn in 3 passes. The deformation rate of the first pass is 12%, the deformation rate of the middle pass is 10%, and the deformation rate of the last pass is 5%. The die angle of the drawing die is 12° and the sizing band length of the die is 0.8mm.

[0171] The concentrate used in steps (2) and (3) has the same composition and ratio. Based on 100 parts by weight of the concentrate, it includes the following components in parts by weight:

[0172] 75 parts of trimethylolpropane oleate;

[0173] 10 parts of extreme pressure anti-wear additive;

[0174] 3.5 parts friction modifier;

[0175] 1 part antioxidant;

[0176] 10 parts of alkylphenol polyoxyethylene ether;

[0177] Benzotriazole 0.5 parts;

[0178] The extreme pressure anti-wear additive is composed of sulfurized olefins, triphenyl thiophosphate and tributyl phosphate in a mass ratio of 1:0.6:0.4; the friction modifier is composed of molybdenum dialkyl dithiocarbamate, glyceryl monooleate and oleic acid in a mass ratio of 1:2:0.7; and the antioxidant is composed of disodium ethylenediaminetetraacetate and L-ascorbic acid in a mass ratio of 1:0.5.

[0179] (4) After the drawing is completed, the grooved line is subjected to a second annealing treatment. It is heated to 500℃ at a heating rate of 10℃ / min and held for 100min. After cooling to room temperature in the furnace, the second annealing treatment is completed. Finally, the grooved line after the second annealing treatment is cleaned by ultrasonic cleaning to obtain the finished grooved line.

[0180] Comparative Example 1

[0181] This comparative example is a method for preparing U-shaped copper groove wire for NbTi / Cu superconducting wire disclosed in Chinese Patent No. CN108735377B, which adopts a three-pass continuous rolling method, specifically:

[0182] The first rolling process involves rolling copper wire from a circle into a rectangle with a width-to-height ratio of 1.5 and a processing rate of 7-10%.

[0183] The second rolling process involves rolling the copper wire from a rectangle into a rectangle with a semi-circular groove on the upper surface, while maintaining the same width, with a processing rate of 4-6%.

[0184] The third rolling process is as follows: the copper wire is rolled from a rectangle with a semi-circular groove on the upper surface into a rectangle with a U-shaped groove on the upper surface. Both the width and thickness have a processing rate of 7~10%.

[0185] The tensile strength of the copper channel wire prepared by this method is 380 MPa (sample 2).

[0186] Comparative Example 2

[0187] In this comparative example, the lubricant in Example 1 was replaced with Kunlun No. 10 aviation hydraulic oil.

[0188] The tensile strength of the irregular copper channel wires prepared in Examples 1-5 and Comparative Example 1 was tested in accordance with the national standard GB / T 228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0189] The Vickers strength of the irregular copper channel wires prepared in Examples 1-5 above was tested in accordance with the national standard GB / T 4340.1-2024 "Metallic materials - Vickers hardness test - Part 1: Test method".

[0190] Extreme pressure performance tests were conducted on the concentrated solutions prepared in Examples 1-5 and the Kunlun No. 10 aviation hydraulic oil used in Comparative Example 2. The extreme pressure performance was quantified by testing the sintering load (PB value) of the lubricant according to GB / T3142-2019 "Determination of Lubricant Load Capacity - Four-Ball Method". The specific test steps are as follows:

[0191] Using a four-ball testing machine, three steel balls are fixed in the lower seat, and the fourth steel ball rotates above (at a speed of 1500 rpm). The concentrated solution prepared in Examples 1-5 is diluted with deionized water at a volume ratio of 1:20 to obtain a lubricant. An appropriate amount of lubricant is injected into the oil cup of the testing machine. The load is gradually increased from a low load until the steel ball sintering is observed. The load value at which sintering occurs is recorded as the PB value. The test is repeated 3 times and the average value is taken.

[0192] The test results are shown in Table 1.

[0193] Table 1 Performance test results of each embodiment and comparative example

[0194]

[0195] According to the test data provided in Table 1, compared with Comparative Example 1, the pure copper channel wires prepared in Examples 1-5 exhibit higher tensile strength and Vickers hardness. Compared with Comparative Example 2, the lubricants prepared in Examples 1-5 exhibit higher sintering load, mainly because:

[0196] On the one hand, Comparative Example 1 employs a multi-pass rolling and drawing process, which, due to the numerous steps and repeated stress introduction, leads to uneven grain structure and residual stress accumulation, ultimately resulting in poor mechanical properties of the product's groove. In contrast, the four-roll mill one-time forming technology used in this invention, through a closed forming cavity composed of the top roll 1, bottom roll 4, and two side support rolls 3, allows the round wire to complete the structural transformation from a circle to a U-shaped groove in a single continuous operation. The direct benefits of this process are: more uniform grain deformation and more consistent microstructure, avoiding defects such as bending and torsion common in traditional processes from the outset. This means that the semi-finished product processed in the subsequent drawing process already possesses excellent metallurgical quality and geometric precision, providing a good performance foundation for ultimately obtaining high and stable mechanical properties (tensile strength, hardness).

[0197] On the other hand, one-time rolling places high demands on the rolls, especially the top roll 1 with the annular protrusion 2. The alloy composition of the top roll 1 specially designed in this invention (high C, W, Mo, V, Co, etc.) endows the top roll 1 with ultra-high high-temperature strength, wear resistance (red hardness) and impact toughness, so that the top roll 1 can always maintain the precise geometry of its annular protrusion 2 under continuous high pressure, thereby ensuring that the groove depth and angle of each rolled groove are highly consistent.

[0198] On the other hand, the present invention uses a relatively dilute lubricant (concentrate:water = 1:15~25) during the rolling process, which provides excellent cooling for the round wire during the rolling process, preventing damage to the round wire and rolls due to overheating, and ensuring the surface finish and microstructure of the rolled groove wire. During the drawing process, a more concentrated lubricant (concentrate:water = 1:5~10) is used, which plays a role in extreme pressure anti-wear. The extreme pressure anti-wear additives (sulfurized olefins, triphenyl thiophosphate, etc.) and friction modifiers (dialkyl dithiocarbamate, molybdenum, etc.) compounded in this invention can form a robust chemical reaction film under high pressure, significantly reducing frictional resistance and deformation heat during drawing. This not only protects the die but also ensures a smooth and uniform drawing deformation process, avoiding problems such as surface scratches, microcracks, or uneven work hardening of the groove wire caused by poor lubrication.

[0199] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper grooves, characterized in that, The rolling and drawing preparation method includes: The semi-finished round wire was subjected to a first annealing treatment under a protective atmosphere, and then the round wire after the first annealing treatment was straightened. The first lubricant is applied to the surface of the straightened round wire, and then the straightened round wire is preheated. The preheated round wire is then fed into a four-roll mill for one-time composite rolling to form a U-shaped cross-section groove wire. A second lubricant is applied to the surface of the rolled groove, and the groove is drawn using a drawing machine; The first lubricant is prepared before use by mixing the concentrate with deionized water at a volume ratio of 1:(15~25). The second lubricant is prepared before use by mixing the concentrate with deionized water at a volume ratio of 1:(5~10) until homogeneous. The concentrate includes synthetic ester base oil, extreme pressure anti-wear additives, friction modifiers, antioxidants, emulsifiers, and corrosion inhibitors; The extreme pressure anti-wear additive includes sulfurized olefins, triphenyl thiophosphate, and tributyl phosphate. The friction modifier includes molybdenum dialkyl dithiocarbamate, glyceryl monooleate, and oleic acid; The antioxidants include disodium ethylenediaminetetraacetate and L-ascorbic acid; After drawing, the grooved wire undergoes a second annealing process and surface cleaning to obtain the finished grooved wire; The four-roll mill includes a top roll (1) at the top of the circular line, a bottom roll (4) at the bottom of the circular line, and support rolls (3) on both sides of the circular line. The surface of the top roll (1) is provided with annular protrusions (2) with a rounded trapezoidal cross-section, which are used to form the groove of the groove line.

2. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper channel as described in claim 1, characterized in that, The semi-finished round wire is made of pure copper. The diameter of the semi-finished round wire is 8~10mm; The protective atmosphere consists of nitrogen and hydrogen, with the hydrogen having a volume fraction of 5-10%. The heating rate of the first annealing treatment is 5~10℃ / min; The target temperature for the first annealing treatment is 500~600℃; The holding time for the first annealing treatment is 60~80 minutes.

3. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper grooves according to claim 1, characterized in that, The round wire after the first annealing treatment is straightened in a multi-roller straightening device; The traveling speed of the round wire after the first annealing treatment in the multi-roller straightening device is 30~50m / min; The tension of the round wire after the first annealing treatment in the multi-roller straightening device is 50~100N.

4. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper grooves according to claim 1, characterized in that, The axes of the top roller (1) and the bottom roller (4) are horizontal and perpendicular to the direction of travel of the circular line; The axis of the support roller (3) is vertical and perpendicular to the direction of travel of the circular line; The chemical composition of the top roller (1) by weight percentage includes: C 1.3~1.5%, W 4~5%, Mo 4.5~5.5%, V 1.8~2.2%, Co 7~8%, Cr 7~9%, Nb 0.1~0.3%, Ni 0.5~1.5%, with the balance being Fe.

5. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper grooves according to claim 1, characterized in that, The straightened round wire is preheated to 180~200℃ and then fed into the four-roll mill; The preheated round wire travels at a speed of 30-40 m / min in the four-roll mill. The tension of the preheated round wire in the four-roll mill is 200~300N; The radius of the rounded trapezoidal section of the annular protrusion (2) is 0.3~0.5mm; The base angle of the rounded trapezoidal cross section of the annular protrusion (2) is 60~70°; The ratio of the height of the annular protrusion (2) to the depth of the finished product groove is 1:(1.1~1.2).

6. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper grooves according to claim 1, characterized in that, The travel speed of the grooved wire inside the drawing machine is 40~50m / min; The drawing process consists of three passes, with the deformation rate of the first pass being 10-12%, the deformation rate of the middle passes being 8-10%, and the deformation rate of the last pass being 3-5%. The die angle of the drawing die is 10~12°; The sizing band length of the drawing die is 0.5~0.8mm.

7. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper channel as described in claim 1, characterized in that, The mass ratio of sulfurized olefins, triphenyl thiophosphate, and tributyl phosphate in the extreme pressure anti-wear additive is 1:(0.5~0.6):(0.3~0.4). The mass ratio of molybdenum dialkyl dithiocarbamate, glyceryl monooleate, and oleic acid in the friction modifier is 1:(1.5~2):(0.5~0.7). The mass ratio of disodium ethylenediaminetetraacetate and L-ascorbic acid in the antioxidant is 1:(0.3~0.5).

8. The method for short-process rolling and drawing of WIC wire with externally coated special-shaped copper grooves according to claim 1, characterized in that, Based on 100 parts by weight of the concentrate, it comprises the following components in parts by weight: 65-75 parts of synthetic ester base oil; 10-12 parts of extreme pressure anti-wear additive; Friction modifier 3-5 parts; 1-2 parts antioxidant; 10-15 parts emulsifier; Corrosion inhibitor 0.5~1 part; The emulsifier is alkylphenol polyoxyethylene ether; The corrosion inhibitor is benzotriazole.

9. A short-process rolling and drawing method for preparing WIC wire with externally coated special-shaped copper channel wire according to claim 1, characterized in that, The heating rate for the second annealing treatment is 5~10℃ / min; The target temperature for the second annealing treatment is 450~500℃; The holding time for the second annealing treatment is 100~120 minutes.

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