High-strength magnetically resistant copper alloy continuous casting process and its application in communication connectors

Abstract

The application discloses a high-strength anti-magnetic copper alloy continuous casting process and application thereof in communication connectors, relates to the field of copper alloy continuous casting processes, and particularly relates to changing the physical structure of non-ferrous metals or non-ferrous alloys in the classification C22F, and comprises the following steps: heating and melting copper materials under a vacuum inert gas environment, performing graded cooling and crystallization and tension straightening to obtain a 111-shaped texture blank of a copper-silver alloy; heating the texture blank, cooling and drawing the texture blank to obtain a wire blank; performing graded heat preservation and slight drawing on the wire blank to obtain a blank for communication connectors; and manufacturing a connector connecting terminal from the blank for communication connectors, wherein the copper matrix is in a 111-shaped columnar texture structure arranged side by side, the internal crystal lattice is in a layered nanometer twin crystal structure, silver precipitated phases are dispersedly distributed at twin crystal boundaries and dislocation positions, and the nanometer twin crystal boundaries and the strong side-by-side columnar preferred orientation of the crystal blank are synergistically used to improve signal integrity and transmission efficiency.

Description

Technical Field

[0001] This invention relates to the field of continuous casting process for copper alloys, and more particularly to a continuous casting process for high-strength antimagnetic copper alloys and its application in communication connectors. Background Technology

[0002] With the rapid development of 5G communication, the Internet of Things, and high-speed data transmission technologies, communication connectors are evolving towards higher frequencies, higher densities, and miniaturization, which places more stringent demands on the core materials of connectors. While traditional copper alloys possess good conductivity and processing properties, their combined performance in terms of high strength and high diamagnetism is insufficient to meet the needs of next-generation communication connectors, especially in applications requiring suppression of electromagnetic interference, reduction of signal transmission loss, and assurance of mechanical durability. Therefore, developing copper alloy materials that combine high strength, excellent diamagnetism, and good conductivity, and achieving efficient and stable manufacturing processes, has become a key focus for both industry and academia.

[0003] Against this backdrop, continuous casting technology for high-strength, antimagnetic copper alloys has emerged. This process achieves efficient forming of alloy billets through continuous casting, while combining composition design and solidification control to effectively refine grains and reduce segregation, thereby improving the overall mechanical and electromagnetic properties of the alloy. Key technologies typically include melt purity control, cooling rate optimization, and electromagnetic stirring to obtain high-quality billets with uniform microstructure and controllable defects during continuous production. This type of process not only improves material production efficiency but also provides a structural basis for subsequent plastic processing and heat treatment, enabling the alloy to significantly improve its strength and antimagnetic properties while maintaining high electrical conductivity. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a high-strength antimagnetic copper alloy continuous casting process and its application in communication connectors.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: a high-strength antimagnetic copper alloy continuous casting process, comprising the following steps:

[0006] S1: The copper material is heated and melted in a vacuum inert gas environment, kept at a constant temperature to degas, cooled and stirred with silver material, and then subjected to graded cooling, crystallization and straightening under high frequency electromagnetic action to obtain a 111-shaped textured blank of copper-silver alloy.

[0007] S2: Heat the fabric blank, keep it at a certain temperature, quench it in water to room temperature, roll it into strip by low-temperature asynchronous rolling, cool and draw it to obtain wire blank;

[0008] S3: Grade and heat-insulate the wire blanks, and then slightly pull them to obtain the blanks for communication connectors;

[0009] S4: The communication connector is made into connector terminals from the blank material.

[0010] In a preferred embodiment of the present invention, in S1, the purity of both copper and silver materials is 99.99%, the vacuum is 4.0×10-3-6.0×10-3 Pa, and the inert gas is one of argon, nitrogen or helium. Specifically, the vacuum inert gas environment is achieved by filling the furnace with inert gas to 0.04-0.06 MPa after the furnace is evacuated to a vacuum.

[0011] In a preferred embodiment of the present invention, in S1, the heating and melting temperature is 1240-1260℃, the holding and degassing time is 10-30 min, the cooling temperature is 1140-1160℃, the stirring frequency is 5-10 Hz, and the stirring time is 5 min.

[0012] In a preferred embodiment of the present invention, in S1, the high-frequency electromagnetic frequency is 40-60kHz, the straightening speed is 0.8-1.2m / min, and the staged cooling is performed by injecting the molten material into the crystallizer and cooling it with cooling water at 19-21°C for primary cooling, with a flow rate of 90-110L / min, and using cooling water at a temperature of 14-16°C for spray cooling.

[0013] In a preferred embodiment of the present invention, in S2, the heating temperature is 945-955℃, the holding time is 0.5-1.5min, the low-temperature asynchronous rolling temperature is 50-100℃, and the asynchronous speed ratio is 1:1.1-1.3.

[0014] In a preferred embodiment of the present invention, in S2, the rolling deformation is 80%-90%, the cooling temperature is 100-150°C, the drawing angle is 10-14°, the drawing speed is 20-25m / s, and the drawing deformation is 10%-15%.

[0015] In a preferred embodiment of the present invention, in S3, the graded heat preservation specifically involves: heat preservation of the wire blank at 370-390℃ for 1-3 hours for the first stage of heat preservation, and heat preservation of the wire blank at 440-460℃ for 3-5 hours for the second stage of heat preservation.

[0016] In a preferred embodiment of the present invention, in S3, the wire blank after graded insulation is drawn again by slight drawing, and the drawing deformation is 3%-5%.

[0017] An application of a high-strength, antimagnetic copper alloy communication connector includes a copper substrate and a silver precipitate phase located on the copper substrate.

[0018] The copper matrix has a columnar texture structure with 111 columns arranged side by side, while its internal lattice is set in a layered nanotwin structure.

[0019] The silver precipitate is dispersed at twin boundaries and dislocations.

[0020] In a preferred embodiment of the present invention, a copper alloy is used in the connection terminals of a communication connector.

[0021] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0022] (1) This application provides a high-strength antimagnetic copper alloy continuous casting process and its application in communication connectors. By combining ultra-high frequency electromagnetic field with ultra-strong directional cooling technology, a crystal blank with strong side-by-side columnar preferred orientation is successfully prepared in the continuous casting stage. This texture feature makes the crystals arranged along the direction of least electron transmission scattering. The high-density coherent nanotwin boundaries introduced by ultra-high speed drawing further refine the grains into a nanoscale layered structure. The strong side-by-side columnar texture provides a low scattering channel for electron movement. As a special interface with low energy and low scattering, the nanotwin boundary not only does not significantly increase the resistance, but also works with the texture to build a continuous high-speed electron channel within the skin depth of the conductor surface, reducing the transmission loss of high frequency current and significantly reducing signal attenuation. Compared with the strong grain boundary scattering and random orientation of ordinary polycrystalline materials in the prior art, the present application improves signal integrity and transmission efficiency through the synergistic effect of nanotwin boundaries and strong side-by-side columnar preferred orientation crystal blanks.

[0023] (2) This application provides a high-strength antimagnetic copper alloy continuous casting process and its application in communication connectors. A multi-scale strengthening system is formed by nano-twin boundaries, Ag precipitates and strong parallel columnar texture. Nano-twin boundaries, as strong dislocation barriers, can effectively hinder dislocation movement and absorb strain energy. Ag precipitates dispersed at twin boundaries and grain boundaries further pin dislocations and stabilize the substructure. As the closest packing surface, the texture itself makes dislocation movement extremely difficult. The three work together to form a strong dislocation movement barrier, making the material extremely resistant to permanent deformation under long-term stress and significantly reducing the stress relaxation rate. Compared with the contact pressure attenuation problem caused by stress relaxation that commonly occurs in materials using a single strengthening mechanism, namely solid solution strengthening or ordinary work hardening, in the prior art, the strengthening mechanism of this application provides more durable and stable mechanical properties. This further ensures the contact reliability of the connector throughout its entire life cycle and eliminates signal interruption failures caused by loose terminals. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional structural diagram of a preferred embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0028] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] As shown in the figure, a continuous casting process for a high-strength, antimagnetic copper alloy includes the following steps:

[0031] S1: The copper material is heated and melted in a vacuum inert gas environment, kept at a constant temperature to degas, cooled and stirred with silver material, and then subjected to graded cooling, crystallization and straightening under high frequency electromagnetic action to obtain a 111-shaped textured blank of copper-silver alloy.

[0032] S2: Heat the fabric blank, keep it at a certain temperature, quench it in water to room temperature, roll it into strip by low-temperature asynchronous rolling, cool and draw it to obtain wire blank;

[0033] S3: Grade and heat-insulate the wire blanks, and then slightly pull them to obtain the blanks for communication connectors;

[0034] S4: The communication connector is made into connector terminals from the blank material.

[0035] It should be noted that this process, by using high-purity copper and silver raw materials and melting them under high vacuum and inert gas protection, ensures the extreme purity of the material matrix, fundamentally eliminating interference from ferromagnetic impurities and laying the foundation for high antimagnetism and excellent conductivity. Subsequently, the high-frequency electromagnetic field applied during the continuous casting stage, combined with directional solidification technology of primary cooling and spray secondary cooling, successfully formed a 111-oriented columnar texture in the copper-silver alloy billet. This structure provides a "high-speed transmission channel" with minimal electron scattering for high-frequency current, effectively alleviating the problem of high-frequency signal loss caused by the skin effect.

[0036] Furthermore, through a drastic plastic deformation process involving low-temperature asynchronous rolling and ultra-high-speed drawing, a high-density layered nanotwin structure was successfully introduced into the textured billet. This structure, acting like a microscopic "dislocation cage," significantly enhances the material's strength and hardness, providing the connector terminals with the ability to resist long-term insertion and extraction stresses and vibration fretting wear. Finally, through a two-stage graded heat treatment, silver atoms were dispersed and precipitated into nanoscale reinforcing phases at twin boundaries and dislocations. This not only further stabilized the microstructure and significantly improved stress relaxation resistance but also optimized electrical conductivity due to the increased purity of the matrix after precipitation.

[0037] S1: The copper material is heated and melted in a vacuum inert gas environment, kept at a constant temperature to degas, cooled and stirred with silver material, and then subjected to graded cooling, crystallization and straightening under high frequency electromagnetic action to obtain a 111-shaped textured blank of copper-silver alloy.

[0038] In a preferred embodiment of the present invention, in S1, the purity of both copper and silver materials is 99.99%, the vacuum is 4.0×10-3-6.0×10-3 Pa, and the inert gas is one of argon, nitrogen or helium. Specifically, the vacuum inert gas environment is achieved by filling the furnace with inert gas to 0.04-0.06 MPa after the furnace is evacuated to a vacuum.

[0039] In a preferred embodiment of the present invention, in S1, the heating and melting temperature is 1240-1260℃, the holding and degassing time is 10-30 min, the cooling temperature is 1140-1160℃, the stirring frequency is 5-10 Hz, and the stirring time is 5 min.

[0040] In a preferred embodiment of the present invention, in S1, the high-frequency electromagnetic frequency is 40-60kHz, the straightening speed is 0.8-1.2m / min, and the staged cooling is performed by injecting the molten material into the crystallizer and cooling it with cooling water at 19-21°C for primary cooling, with a flow rate of 90-110L / min, and using cooling water at a temperature of 14-16°C for spray cooling.

[0041] It should be noted that the core objective of step S1 in this process is to prepare a high-purity copper-silver alloy billet with a specific crystallographic orientation. This step uses high-purity copper and silver materials, and after melting in a high vacuum environment, it is filled with an inert protective gas. This measure eliminates the introduction of magnetic impurity elements such as iron (Fe), cobalt (Co), and nickel (Ni) to the greatest extent, ensuring the excellent antimagnetic properties of the material from the source, and providing a pure matrix condition for obtaining high electrical conductivity.

[0042] During the smelting process, the copper material is heated to 1240-1260℃ and held for 10-30 minutes. This not only ensures complete melting but also plays a crucial role in degassing, effectively removing gases such as hydrogen and oxygen from the melt and further improving the purity of the metal. Subsequently, the temperature is lowered to 1140-1160℃, and silver is added. The mixture is then electromagnetically stirred at a frequency of 5-10Hz for 5 minutes. This operation ensures the uniform distribution of silver in the copper melt, avoiding gravity segregation and laying the compositional foundation for obtaining a textured billet with uniform composition and consistent properties.

[0043] Furthermore, the continuous casting process is conducted under the influence of a 40-60kHz high-frequency electromagnetic field. This electromagnetic field effectively refines the grains and controls the convection of the melt, guiding the crystals to preferentially grow along the heat flow direction with the optimal <111> crystal orientation. Combined with a straightening speed of 0.8-1.2 m / min and a staged cooling process—firstly, primary cooling with cooling water at 19-21℃ and a flow rate of 90-110 L / min, followed by intense spray cooling with cooling water at 14-16℃—this creates a strong directional heat flow environment. This environment, in conjunction with the high-frequency electromagnetic field, produces a synergistic effect, ultimately successfully solidifying the billet into a columnar crystal structure dominated by a strong <111> texture. This texture is the most densely packed crystal orientation with the least electron transport scattering in face-centered cubic metals. Its formation ensures that when the billet is subsequently processed into connector terminals, the skin effect layer for high-frequency current is precisely composed of the crystal face with the best conductivity, thus providing a unique structural advantage for fundamentally solving the technical challenge of high-frequency signal transmission loss.

[0044] S2: Heat the fabric blank, keep it at a certain temperature, quench it in water to room temperature, roll it into strip by low-temperature asynchronous rolling, cool and draw it to obtain wire blank;

[0045] In a preferred embodiment of the present invention, in S2, the heating temperature is 945-955℃, the holding time is 0.5-1.5min, the low-temperature asynchronous rolling temperature is 50-100℃, and the asynchronous speed ratio is 1:1.1-1.3.

[0046] In a preferred embodiment of the present invention, in S2, the rolling deformation is 80%-90%, the cooling temperature is 100-150°C, the drawing angle is 10-14°, the drawing speed is 20-25m / s, and the drawing deformation is 10%-15%.

[0047] It should be noted that step S2 of this process follows the textured billet obtained in step S1. This step first involves heating the billet with the 111-shaped texture at 945-955℃ for a short time (0.5-1.5 min) and holding it thereafter, followed by water quenching. This solution treatment allows the silver atoms to completely dissolve in the copper matrix to form a supersaturated solid solution, creating the necessary conditions for subsequent aging precipitation. At the same time, rapid cooling fixes the high-temperature state to room temperature, avoiding grain growth or compositional segregation. Subsequently, an asynchronous rolling process with a low-temperature environment of 50-100℃ and a speed ratio of 1:1.1-1.3 is used to apply a huge deformation of 80%-90% to the billet. The combined effect of the strong shear strain generated by asynchronous rolling and the suppression of dynamic recrystallization by low temperature causes the dislocation density inside the material to increase sharply and effectively promotes mechanical twinning, thereby successfully introducing a high-density layered nanotwin structure on the basis of the original texture.

[0048] Subsequently, the rolled strip was drawn at a controlled temperature of 100-150℃, with a drawing angle of 10-14° and an ultra-high speed of 20-25m / s. This high-speed deformation condition further promoted the proliferation and refinement of nanotwins and transformed the microstructure into a uniform fibrous structure. This nanotwin structure, as a strong dislocation barrier, significantly improved the material's strength and resistance to fretting wear. Furthermore, its special coherent interface has minimal electron scattering, allowing the material to maintain excellent conductivity while achieving high strength. This effectively solves the traditional problem of the mutual constraint between strength and conductivity in connector materials. Therefore, step S2, through the combination of solution treatment, low-temperature asynchronous rolling, and ultra-high-speed drawing, successfully transformed the textured blank of S1 into a wire blank filled with layered nanotwins, providing an ideal structural substrate for the aging precipitation of S3, and ultimately achieving a synergistic improvement in strength and conductivity.

[0049] S3: Grade and heat-insulate the wire blanks, and then slightly pull them to obtain the blanks for communication connectors;

[0050] In a preferred embodiment of the present invention, in S3, the graded heat preservation specifically involves: heat preservation of the wire blank at 370-390℃ for 1-3 hours for the first stage of heat preservation, and heat preservation of the wire blank at 440-460℃ for 3-5 hours for the second stage of heat preservation.

[0051] In a preferred embodiment of the present invention, in S3, the wire blank after graded insulation is drawn again by slight drawing, and the drawing deformation is 3%-5%.

[0052] It should be noted that step S3 of this process uses precise heat treatment and slight deformation processing to stabilize and strengthen the special microstructure constructed in the previous steps, thereby fully stimulating the comprehensive performance potential of the material. The wire blank obtained in step S2, which already has a high-strength nanotwin structure, is subjected to graded heat preservation treatment. First, a first-stage heat preservation is carried out at 370-390℃ for 1-3 hours. The main purpose of this stage is to promote the segregation of silver atoms supersaturated in the copper matrix at high-energy defects such as nanotwin boundaries, ordinary grain boundaries, and high-density dislocations, forming a large number of dispersed and fine Ag atom clusters. This provides a large number of nucleation sites for subsequent precipitation and initially strengthens the matrix. Then, a second-stage heat preservation is carried out at 440-460℃ for 3-5 hours. This stage provides sufficient diffusion kinetic energy for silver atoms at a higher temperature, allowing them to grow into nanoscale Ag precipitates with controllable size and uniform distribution.

[0053] Through a multi-stage thermal insulation process, silver (Ag) precipitates preferentially form at highly stable coherent nanotwin boundaries. These precipitates act as robust pinning points, significantly stabilizing the twin structure and effectively hindering dislocation movement under long-term stress. This significantly enhances the material's resistance to stress relaxation, resolving signal interruption issues caused by contact pressure attenuation at connector terminals. Simultaneously, the substantial precipitation of silver from the copper matrix drastically reduces lattice distortion and electron scattering centers, resulting in a significant recovery of the material's conductivity while maintaining high strength. This perfectly balances the traditional contradiction between strength and conductivity.

[0054] After graded heat preservation, a slight drawing process with a deformation of only 3%-5% is applied to the wire blank. The purpose of this processing is not to further increase the strength significantly, but to eliminate the slight yield plateau that may occur during aging, so that the material can obtain better elasticity and consistent mechanical properties. At the same time, it further improves the surface finish and dimensional accuracy of the wire, ensuring that it meets the final shape and tolerance requirements of the precision terminals of communication connectors. Therefore, the S3 step, through the combination of graded heat preservation and slight drawing technology, finally transforms the intermediate product of S2 into a communication connector blank with ultra-high strength, excellent electrical conductivity and excellent stress relaxation resistance, providing a perfect material basis for the final precision forming in S4.

[0055] An application of a high-strength antimagnetic copper alloy communication connector includes a copper substrate and a silver precipitate on the copper substrate. The copper substrate has a columnar texture structure with 111 columns arranged side by side, and its internal lattice is set in a layered nanotwin structure. The silver precipitate is dispersed at the twin boundaries and dislocations.

[0056] In a preferred embodiment of the present invention, a copper alloy is used in the connection terminals of a communication connector.

[0057] The core design principle of this solution lies in constructing a special material that can synergistically solve multiple core pain points of high-speed communication connectors by controlling the microstructure. This allows for the preparation of a copper alloy that combines extremely high strength, excellent high-frequency conductivity, outstanding resistance to stress relaxation and fretting wear, while maintaining its inherent antimagnetic properties.

[0058] By employing ultra-high purity copper-silver raw materials and applying ultra-high frequency electromagnetic fields and ultra-strong directional cooling during continuous casting to control the solidification process, columnar billets with a preferred crystal orientation (texture) of 111-shaped side-by-side columnar crystals were obtained. This texture is the closest-packed crystal orientation with the least electron transport scattering in face-centered cubic metals. Next, the billet underwent intense plastic deformation, namely asynchronous rolling and ultra-high-speed drawing. During this process, high-density coherent nanotwin boundaries were introduced in a controlled manner, forming a layered nanotwin structure. Twin boundaries are special grain boundaries with low energy and high stability, exhibiting extremely weak electron scattering and effectively hindering dislocation movement. Finally, through multi-stage aging heat treatment, the microalloying element silver (Ag) was dispersed and precipitated at the twin boundaries and grain boundaries, further pinning dislocations and stabilizing the microstructure.

[0059] This solution, through a sophisticated synergistic design of texture, nanotwins, and precipitates, constructs a multi-layered, functionally integrated microstructure, perfectly solving the core technical challenges faced by high-speed communication connectors. The formation of a 111-shaped, side-by-side columnar texture structure achieves optimal crystallographic orientation, which, as the lowest scattering path for electron transport, significantly improves the transmission efficiency of high-frequency current in the conductor's skin effect layer. The introduction of high-density nanotwin boundaries, without compromising conductivity, effectively hinders dislocation movement through its unique coherent interface structure, providing the material with exceptional strength and hardness. Furthermore, Ag nanoprecipitates, achieved through multi-stage thermal insulation, preferentially disperse at twin and grain boundaries. These precipitates not only act as additional dislocation pinning points, significantly enhancing the material's resistance to plastic deformation, but also significantly improve electrical conductivity by purifying the copper matrix.

[0060] By employing nanotwins and precipitates to provide reinforcement while minimizing their impact on electron scattering, the intrinsic high conductivity inherent in the textured structure is perfectly preserved. The presence of the texture ensures that even at millimeter-wave frequencies, the surface layer through which current concentrates remains composed of the optimal conductive crystal orientation, reducing high-frequency signal loss. Simultaneously, the composite reinforcement mechanism jointly constructed by nanotwin boundaries and Ag precipitates enhances the material's resistance to stress relaxation, effectively guaranteeing the contact stability of connector terminals under long-term insertion and extraction stress. The high strength and excellent work hardening capability brought by the surface nanotwin structure allow the material's surface to continuously harden during fretting wear rather than generating oxide debris, reducing wear depth and ensuring that contact resistance remains stable throughout the device's lifespan. This synergistic design of the microstructure magically transforms traditionally contradictory performance indicators—strength, conductivity, stress relaxation resistance, and wear resistance—into a mutually reinforcing organic whole.

[0061] Example 1

[0062] At 5.0×10 -3Argon gas was introduced into a vacuum environment to a pressure of 0.05 MPa. 99.99% copper material was heated and melted at a temperature of 1250℃. After holding at this temperature for 20 min to degas, 99.99% silver material was added and stirred at a frequency of 7 Hz for 5 min. The mixture was then subjected to staged cooling, crystallization, and straightening under the action of high-frequency electromagnetic force at a frequency of 50 kHz and a straightening speed of 1.0 m / min. Staged cooling involved injecting the molten material into a crystallizer and then cooling it with cooling water at 20℃ at a flow rate of 100 L / min. The cooling water was then spray-cooled at a temperature of 15℃ to obtain a copper-silver alloy with a 111-shaped textured blank.

[0063] The fabric blank is heated to 950℃ and held for 1 minute. It is then water-quenched to room temperature and rolled into strip by low-temperature asynchronous rolling at 80℃ with an asynchronous speed ratio of 1:1.2 and a rolling deformation of 85%. The strip is then cooled and drawn at 125℃ with a drawing angle of 12° and a drawing speed of 22 m / s, resulting in a drawing deformation of 13% to obtain wire blank.

[0064] The wire blanks are subjected to graded heat preservation. Specifically, the wire blanks are heat-preserved at 380℃ for 2 hours for the first stage of heat preservation, and heat-preserved at 450℃ for 4 hours for the second stage of heat preservation. They are then slightly pulled with a pulling deformation of 4% to obtain the blanks for communication connectors. The blanks for communication connectors are then used to make connector terminals.

[0065] Experiment 1:

[0066] Based on Example 1, and using Example 1 as a control group, the high-frequency electromagnetic frequency in the preparation of the textured material, the water temperature during spray cooling, and the drawing speed during the preparation of the nanotwinned structure were changed to prepare several experimental groups. The experimental and control groups were then fabricated into connection terminals of the same shape and size as test pieces. Using a vector network analyzer, the test pieces were connected to a VNA, and measurements were performed from 1 GHz to 40 GHz. Full two-port calibration was performed using the SOLT (Short-Open-Load-Thru) calibration method to eliminate systematic errors. This allowed for precise measurement of the test piece's scattering parameters in the frequency domain, namely return loss and VSWR, using the VNA. A cable for a 10 GHz application was tested; details are shown in Table 1.

[0067] Table 1

[0068]

[0069] As shown in Table 1, the high-frequency electromagnetic frequency and the spray cooling water temperature work together to determine the solidification process during the preparation of textured billets. The main role of the high-frequency electromagnetic field is the magnetohydrodynamic effect it generates. It can effectively stir the melt, break up the initially formed dendrites, significantly refine the grains, and create initial conditions for the preferential growth of grains. More importantly, the electromagnetic field of a specific frequency can couple with the inherent characteristics of the molten metal, guiding the free grains to grow in the direction of the heat flow in the most densely packed and lowest-energy direction of the face-centered cubic crystal, which is the 111-shaped side-by-side arrangement. At the same time, the ultra-low water temperature of the spray cooling establishes an extremely large temperature gradient at the solidification interface, ensuring that the solidification process proceeds unidirectionally at an extremely high rate. This strong directional heat flow is the fundamental physical guarantee for the stable and continuous growth of the side-by-side columnar texture and its eventual dominance. If the water temperature is too high and the temperature gradient is insufficient, it will lead to the formation of equiaxed crystals, destroying the uniformity and continuity of the texture.

[0070] In the subsequent preparation of nanotwin structures, a high strain rate is applied to the material at a low temperature, causing the nucleation and movement rate of dislocations to far exceed their dynamic recovery rate, resulting in a rapid accumulation of dislocation density. When the local stress generated by dislocation pile-up reaches a critical value, the material will coordinate the huge plastic strain in a mechanical twinning manner rather than simply dislocation slip, thereby generating high-density coherent nanotwin boundaries in a controlled and uniform manner. These twin boundaries are a near-perfect crystallographic interface with extremely low interface energy, and their scattering effect on conduction electrons is much weaker than that of ordinary high-energy grain boundaries.

[0071] The parallel columnar texture and nanotwin boundaries together optimize the electron transport path within the conductor's skin depth. First, the parallel columnar crystal orientation is the direction of the densest atomic arrangement in copper crystals, resulting in minimal lattice scattering when electrons move in this direction, essentially creating a natural "highway" for electrons. The introduction of nanotwin boundaries, without significantly increasing electron scattering, greatly refines the grains and hinders dislocation movement. These low-scattering twin boundaries further divide the interior of the strongly parallel-oriented grains into countless parallel nanoscale thin sheets with consistent orientation. On the conductor surface where high-frequency current mainly flows, the current is confined to this "high-speed electron channel" network composed of textured grains and low-scattering twin boundaries. During electron movement, the strong scattering caused by ordinary disordered grain boundaries is avoided, and the resistance to movement within the crystal orientation is reduced, thereby significantly reducing overall resistance loss and solving the signal attenuation problem caused by the high-frequency skin effect.

[0072] Experiment 2

[0073] Using Example 1 as the control group, and in Experiment 1, the high-frequency electromagnetic frequency in the preparation of the textured material, the water temperature during spray cooling, and the drawing speed during the preparation of the nanotwinned structure were all changed to prepare several experimental groups. Furthermore, the temperature during the first-stage heat preservation was also changed to prepare several experimental groups. These experimental and control groups were used as test pieces, which were then fabricated into connection terminals for communication connectors. The connection terminals were subjected to an initial stress of 100 MPa at 150°C and compressed. The residual stress was measured using a stress relaxation testing machine within 100 hours. After 100 hours, the stress relaxation rate was calculated as: [(initial stress - residual stress) / initial stress]. 100% stress relaxation rate was calculated, see Table 2 for details.

[0074] Table 2

[0075]

[0076] As shown in the table, higher frequencies generate stronger magnetohydrodynamic effects during the preparation of billets with parallel columnar textures, resulting in more thorough breakage and screening of dendrites in the melt, while suppressing solute segregation and creating initial conditions for the formation of highly oriented columnar crystals. However, the frequency must be matched with the power and casting speed. Too high a frequency may lead to an excessively strong skin effect, with energy concentrated too much on the surface; too low a frequency results in insufficient stirring force, making it impossible to effectively control the solidification front. This is complemented by the lower spray water temperature in ultra-strong directional cooling. Water temperature (such as near room temperature) can establish a huge axial temperature gradient. This huge thermal gradient is the fundamental driving force for the formation of directional solidification. It ensures that the grains can grow rapidly and competitively against the direction of heat flow. Those grains with parallel columnar texture structures whose crystal orientation is parallel to the direction of heat flow will eventually win and dominate due to their fastest growth rate, thus forming a strong texture. Therefore, the frequency of the electromagnetic field controls the initial nucleation and solute distribution of solidification, while the spray water temperature controls the competitive growth and orientation selection of the grains. The two work together to finally prepare a columnar crystal structure with strong parallel preferred orientation.

[0077] Furthermore, during the subsequent intense plastic deformation, the speed parameters of asynchronous rolling and ultra-high-speed drawing are crucial for introducing high-density nanotwins. The extremely high strain rate causes the rate of dislocation proliferation and movement to far exceed its dynamic recovery rate, leading to rapid dislocation pile-up and extremely high local stress concentration. When this stress reaches the twinning critical shear stress, the material will deform in a coordinated manner through mechanical twinning, forming a large number of coherent nanotwin boundaries. This process is similar to a sudden acceleration in traffic flow causing dense traffic jams, ultimately forcing the traffic to open new parallel lanes. The drawing speed directly determines the strain rate, thereby determining the efficiency of dislocation pile-up and the density of twin formation. The subsequent first-stage aging temperature is important because it precisely controls the precipitation behavior of the microalloying element silver (Ag). Choosing a relatively low temperature is to ensure sufficient precipitation driving force while limiting the diffusion ability of atoms. This forces Ag atoms to preferentially nucleate and precipitate at locations with higher crystal defect energy—namely, the abundant nanotwin boundaries and ordinary grain boundaries—forming a diffusely distributed nanoscale precipitate phase. If the temperature is too high, Ag atoms diffuse too quickly, and the precipitates will mainly coarsen and grow within the crystal, which not only weakens the strengthening effect but also severely scatters electrons and impairs conductivity.

[0078] Ultimately, these microstructural components—strongly parallel columnar texture, nanotwins, and Ag precipitates—collectively form a powerful, multi-layered, synergistic barrier, enabling the material to resist permanent deformation under long-term stress. The underlying mechanism lies in the fact that stress relaxation essentially involves the slip, reorganization, and annihilation of dislocations within the material under constant strain, leading to a gradual decrease in the stress maintaining deformation. This synergistic system comprehensively hinders this process from three angles. First, the strongly parallel columnar texture ensures that the slip system orientation of most grains tends to be consistent. This means that dislocations are unlikely to trigger slip between adjacent grains with significantly different orientations, i.e., they are unlikely to cross ordinary large-angle grain boundaries. Their movement is restricted to a longer path, thus increasing the overall resistance to dislocation movement. Second, the nanotwin boundaries distributed throughout the grains constitute a large number of low-energy, stable coherent interfaces, which act as crucial traversal points for dislocations during their movement. Countless "nanoscale fences" effectively absorb, reflect, and dissipate the kinetic energy of dislocations. Each interaction between a dislocation and a twin boundary—whether cutting or piling up there—dissipates energy, greatly slowing down the macroscopic movement and recombination of dislocations. Finally, the nanoscale Ag phases dispersed at twin and grain boundaries act as "pinning points," effectively anchoring dislocations and preventing the climbing motion most likely to occur under long-term high-temperature stress. This significantly stabilizes the entire dislocation structure. These three elements complement each other: texture provides macroscopic orientation constraints, nanotwins provide a microscopic barrier network, and precipitated phases provide atomic-scale pinning points. Together, they efficiently absorb and dissipate external mechanical energy (strain energy) internally, converting it into more stable forms such as interfacial energy, rather than allowing dislocations to release energy through slip and recombination, leading to permanent deformation. This results in extremely strong resistance to stress relaxation.

[0079] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A continuous casting process for high-strength, antimagnetic copper alloy, characterized in that, Includes the following steps: S1: The copper material is heated and melted in a vacuum inert gas environment, kept at a constant temperature to degas, cooled and stirred with silver material, and then subjected to graded cooling, crystallization and straightening under high frequency electromagnetic action to obtain a 111-shaped textured blank of copper-silver alloy. S2: Heat the fabric blank, keep it at a certain temperature, quench it in water to room temperature, roll it into strip by low-temperature asynchronous rolling, cool and draw it to obtain wire blank; S3: Grade and heat-insulate the wire blanks, and then slightly pull them to obtain the blanks for communication connectors; S4: The communication connector is made into connector terminals from the blank material; The high-frequency electromagnetic frequency is 40-60kHz; the staged cooling involves injecting the molten material into the crystallizer and performing primary cooling with cooling water at 19-21℃, with a flow rate of 90-110L / min, using cooling water at a temperature of 14-16℃ for spray cooling.

2. The continuous casting process for a high-strength, antimagnetic copper alloy according to claim 1, characterized in that: In step S1, both the copper and silver materials have a purity of 99.99%, and the vacuum is 4.0 × 10⁻⁶. -3 -6.0×10 -3 Pa, the inert gas is one of argon, nitrogen or helium, and the vacuum inert gas environment is specifically defined as filling the furnace with inert gas to 0.04-0.06 MPa after the furnace is evacuated to a vacuum.

3. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S1, the heating and melting temperature is 1240-1260℃, the holding and degassing time is 10-30 min, the cooling temperature is 1140-1160℃, the stirring frequency is 5-10 Hz, and the stirring time is 4-6 min.

4. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S1, the straightening speed is 0.8-1.2 m / min.

5. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S2, the heating temperature is 945-955℃, the holding time is 0.5-1.5min, the low-temperature asynchronous rolling temperature is 50-100℃, and the asynchronous speed ratio is 1:1.1-1.

3.

6. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S2, the rolling deformation is 80%-90%, the cooling temperature is 100-150℃, the drawing angle is 10-14°, the drawing speed is 20-25m / s, and the drawing deformation is 10%-15%.

7. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S3, the graded insulation specifically involves: first-stage insulation, where the wire blank is kept at 370-390℃ for 1-3 hours; and second-stage insulation, where the wire blank is kept at 440-460℃ for 3-5 hours.

8. The continuous casting process for high-strength antimagnetic copper alloy according to claim 1, characterized in that: In S3, the wire blank after graded insulation is drawn again by slight drawing, and the drawing deformation is 3%-5%.

9. An application of a high-strength antimagnetic copper alloy communication connector, based on a connection terminal prepared by the continuous casting process described in claims 1-8, comprising a copper substrate and a silver precipitate phase located on the copper substrate, characterized in that: The copper matrix has a columnar texture structure with 111 columns arranged side by side, while its internal lattice is set in a layered nanotwin structure. The silver precipitates are dispersed at twin boundaries and dislocations.

10. The application of the high-strength antimagnetic copper alloy communication connector according to claim 9, characterized in that: The copper alloy is used in the connection terminals of the communication connector.

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