Corrosion-resistant steel-cored aluminum strand and method for manufacturing the same

Abstract

This invention discloses a corrosion-resistant steel-cored aluminum stranded wire and its preparation method, relating to the field of electrical engineering technology. The corrosion-resistant steel-cored aluminum stranded wire includes a steel core and aluminum wire stranded around the steel core. The surface of the steel core is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The surface of the aluminum wire is coated with a porous anodic oxide film formed by anodizing and sealing treatment. This invention achieves dual protection for the steel core by sequentially applying a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating to the surface of the steel core. Therefore, it can solve the problem that existing steel cores are easily corroded in complex corrosive environments, leading to a decline in the overall performance and a shortened service life of the steel-cored aluminum stranded wire.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering technology, specifically to a corrosion-resistant steel-cored aluminum stranded wire and its preparation method. Background Technology

[0002] Corrosion-resistant steel-cored aluminum stranded wire is an overhead transmission conductor that combines high strength and corrosion resistance. It can effectively reduce rust in corrosive environments such as humid, coastal or industrial areas, extend the service life of the conductor, ensure the stable operation of transmission lines, and take into account structural strength, conductivity and weather resistance.

[0003] In existing technologies, corrosion-resistant steel-cored aluminum stranded wires typically employ a single coating or traditional zinc plating on the steel core. The aluminum wire surface treatment is simple, and the overall structural design suffers from deficiencies in mechanical properties, environmental adaptability, and operational monitoring. This makes them susceptible to corrosion in complex corrosive environments such as humid, coastal, or industrial areas, shortening their service life and affecting the stable operation of transmission lines. Furthermore, their conductivity and fatigue resistance are insufficient to meet the demands of harsh operating conditions. Therefore, this invention provides a corrosion-resistant steel-cored aluminum stranded wire and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a corrosion-resistant steel-cored aluminum stranded wire and its preparation method. This invention employs a dual protection method, applying a Zn-Al-Mg alloy coating and a Ni-P-SiC composite coating to the steel core, and anodizing and treating the aluminum wire with a specific sealing liquid. Combined with variable pitch stranding, the addition of corrosion inhibitor microcapsules to the gaps, the filling of the hollow steel core with damping materials, and the integration of sensors, the invention significantly improves the corrosion resistance, conductivity stability, mechanical strength, fatigue resistance, and operational monitoring capabilities of the steel-cored aluminum stranded wire, thus adapting it to complex and harsh operating environments.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A corrosion-resistant steel-cored aluminum stranded wire includes a steel core and aluminum wire stranded around the steel core; The surface of the steel core is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The thickness of the Zn-Al-Mg alloy coating is 30-40 μm, wherein the mass fraction of Zn is 85%-90%, the mass fraction of Al is 8%-12%, and the mass fraction of Mg is 2%-3%. The Ni-P-SiC composite coating has a thickness of 10–15 μm, and the plating solution contains NiSO4. The concentration of 6H2O is 250-300 g / L, and NaH2PO2 The concentration of H2O is 20-30 g / L, and the particle size of SiC particles is 0.5-1 μm and the concentration is 10-15 g / L; The aluminum wire surface is provided with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 15-20 μm. The concentration of K2SiF6 in the sealing solution is 15-20 g / L, the concentration of La(NO3)3 is 5-8 g / L, the sealing temperature is 80-90℃, the sealing time is 20-30 min, and the sealing solution also contains 0.5%-1% by mass nano-titanium dioxide particles.

[0006] Preferably, microcapsules containing a corrosion inhibitor are uniformly dispersed in the gap between the steel core and the aluminum wire strand, wherein the corrosion inhibitor is benzotriazole; The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 5-10 μm, and the corrosion inhibitor content accounts for 30%-40% of the mass of the microcapsules.

[0007] Preferably, the steel core has a hollow structure, the diameter of the hollow part is 1 / 3 to 1 / 2 of the overall outer diameter of the steel core, and the hollow part is filled with a damping material, the damping material being butyl rubber with a damping coefficient greater than 0.3.

[0008] Preferably, the aluminum wire adopts a variable pitch stranding method, in which the stranding pitch of the aluminum wire gradually increases from the inner layer to the outer layer, and the ratio of the stranding pitch of two adjacent layers of aluminum wire is 1.1 to 1.3.

[0009] Preferably, the steel core also integrates a miniature corrosion sensor and a stress sensor; The corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance spectroscopy, with dimensions of 0.5mm × 0.5mm × 0.2mm. The stress sensor is a sensor using fiber Bragg grating technology with a diameter of 0.1 mm; The miniature corrosion sensor and stress sensor transmit data to the monitoring center via a miniature wireless transmission module using low-power Bluetooth or LoRa wireless communication.

[0010] Preferably, the surface of the steel core is first coated with a Zn-Al-Mg alloy by hot-dip galvanizing at a temperature of 450–480°C for 3–5 min. Then, a Ni-P-SiC composite coating is deposited by chemical plating at a pH of 4.5–5.5 and a temperature of 85–95°C. A magnetic stirrer is used to stir the coating at a speed of 200–300 r / min.

[0011] Preferably, when the aluminum wire is anodized, the electrolyte is a sulfuric acid solution with a mass fraction of 15% to 20%, the anolyte current density is 1.5 to 2.5 A / dm², and the oxidation time is 30 to 40 min.

[0012] Preferably, the preparation method includes the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:3 to 1:5 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

[0013] Preferably, during the preparation of microcapsules, the reaction temperature is controlled at 60-70℃, the reaction time is 2-3h, the stirring speed is 150-250r / min, the emulsifier is sodium dodecyl sulfate with a mass fraction of 0.5%-1%, and the dropping rate of urea-formaldehyde prepolymer is 1-2 drops / s.

[0014] Preferably, the hollow steel core is made of seamless steel pipe with a wall thickness of 3-5mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. Before filling, the damping material is preheated to 60-70℃ and filled by pressure injection at a pressure of 0.5-1MPa, achieving a filling rate of 95%-98%. After filling, both ends of the steel core are sealed.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves dual protection for the steel core by sequentially depositing a hot-dip galvanized Zn-Al-Mg alloy coating and a chemically deposited Ni-P-SiC composite coating on the steel core surface. Compared with single coatings or traditional zinc plating in existing technologies, this invention improves the corrosion resistance of the steel core. The Zn-Al-Mg alloy coating itself has good corrosion resistance, and the Ni-P-SiC composite coating further enhances the protective capability. Therefore, it can solve the problem that existing steel cores are easily corroded in complex corrosive environments, leading to a decline in the overall performance and a shortened service life of steel-cored aluminum stranded wire.

[0016] 2. This invention achieves the formation of a high-performance porous anodic oxide film on the surface of aluminum wire by anodizing and sealing the aluminum wire, and adding specific concentrations of K2SiF6, La(NO3)3, and nano-titanium dioxide particles to the sealing solution. Compared with existing aluminum wire surface treatment methods, this invention improves the corrosion resistance of the aluminum wire. The porous anodic oxide film effectively blocks the erosion of corrosive media, and the synergistic effect of the components in the sealing solution enhances the stability and protective properties of the oxide film. Therefore, it can solve the problem of corrosion affecting the conductivity and mechanical properties of aluminum wire during long-term use.

[0017] 3. This invention improves the overall performance of steel-cored aluminum stranded wire by employing a variable-pitch stranding method, uniformly dispersing microcapsules containing corrosion inhibitors in the stranding gaps between the steel core and aluminum wire, designing the steel core as a hollow structure filled with damping material, and integrating micro-corrosion and stress sensors within the steel core. Compared with existing technologies, this invention enhances the structural stability, self-healing ability, damping and vibration reduction capabilities, and real-time monitoring capabilities of the stranded wire, thus addressing the shortcomings of existing steel-cored aluminum stranded wires in terms of mechanical properties, handling complex environments, and operational status monitoring. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention have been clearly and completely described. 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.

[0019] This embodiment provides a corrosion-resistant steel-cored aluminum stranded wire, including a steel core and aluminum wire stranded around the steel core; The steel core surface is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The thickness of the Zn-Al-Mg alloy coating is 30-40 μm, wherein the mass fraction of Zn is 85%-90%, the mass fraction of Al is 8%-12%, and the mass fraction of Mg is 2%-3%. The Ni-P-SiC composite coating thickness is 10–15 μm, and the NiSO4 content in the plating bath is [missing information]. The concentration of 6H2O is 250-300 g / L, and NaH2PO2 The concentration of H2O is 20-30 g / L, and the particle size of SiC particles is 0.5-1 μm and the concentration is 10-15 g / L; The aluminum wire surface is covered with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 15-20 μm. The concentration of K2SiF6 in the sealing solution is 15-20 g / L, the concentration of La(NO3)3 is 5-8 g / L, the sealing temperature is 80-90℃, the sealing time is 20-30 min, and the sealing solution also contains 0.5%-1% nano-titanium dioxide particles by mass.

[0020] In some embodiments, microcapsules containing a corrosion inhibitor are uniformly dispersed in the gaps between the steel core and the aluminum wire strands. The corrosion inhibitor is benzotriazole. The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 5-10 μm, and the corrosion inhibitor content accounts for 30%-40% of the mass of the microcapsules.

[0021] In some embodiments, the steel core is a hollow structure, the diameter of the hollow part is 1 / 3 to 1 / 2 of the overall outer diameter of the steel core, and the hollow part is filled with damping material, which is butyl rubber with a damping coefficient greater than 0.3.

[0022] In some embodiments, the aluminum wires are stranded in a variable pitch manner, with the stranding pitch of the aluminum wires gradually increasing from the inner layer to the outer layer, and the ratio of the stranding pitch of two adjacent layers of aluminum wires being 1.1 to 1.3.

[0023] In some embodiments, the steel core also integrates a miniature corrosion sensor and a stress sensor; The corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance, with dimensions of 0.5mm × 0.5mm × 0.2mm; The stress sensor is a fiber Bragg grating sensor with a diameter of 0.1 mm. Miniature corrosion sensors and stress sensors transmit data to the monitoring center via ultra-miniature wireless transmission modules using low-power Bluetooth or LoRa wireless communication.

[0024] In some embodiments, a Zn-Al-Mg alloy coating is first formed on the surface of the steel core by a hot-dip galvanizing process at a temperature of 450–480°C and a dip time of 3–5 min. Then, a Ni-P-SiC composite coating is deposited by chemical plating, with a pH of 4.5–5.5 and a temperature of 85–95°C. A magnetic stirrer is used to stir at a speed of 200–300 r / min.

[0025] In some embodiments, when the aluminum wire is anodized, the electrolyte is a sulfuric acid solution with a mass fraction of 15% to 20%, the anodic current density is 1.5 to 2.5 A / dm², and the oxidation time is 30 to 40 min.

[0026] In some embodiments, the preparation method includes the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:3 to 1:5 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

[0027] In some embodiments, during microcapsule preparation, the reaction temperature is controlled at 60–70°C, the reaction time is 2–3 h, the stirring speed is 150–250 r / min, the emulsifier is sodium dodecyl sulfate with a mass fraction of 0.5%–1%, and the urea-formaldehyde prepolymer is added at a dropping rate of 1–2 drops / s.

[0028] In some embodiments, the hollow steel core is made of seamless steel pipe with a wall thickness of 3-5mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. Before filling, the damping material is preheated to 60-70℃ and filled by pressure injection at a pressure of 0.5-1MPa, achieving a filling rate of 95%-98%. After filling, both ends of the steel core are sealed.

[0029] Based on the foregoing embodiments, the following sets of experiments were conducted: It should be noted that the raw materials used in the following embodiments are all commercially available.

[0030] Example 1: A corrosion-resistant steel-cored aluminum stranded wire, comprising a steel core and aluminum wire stranded around the steel core; The steel core surface is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The Zn-Al-Mg alloy coating has a thickness of 30 μm, wherein the mass fraction of Zn is 85%, the mass fraction of Al is 12%, and the mass fraction of Mg is 3%. The Ni-P-SiC composite coating has a thickness of 10 μm, and the NiSO4 content in the plating bath is [missing information]. The concentration of 6H2O is 250 g / L, and the concentration of NaH2PO2 is... The concentration of H2O is 20 g / L, and the particle size of SiC is 0.5 μm with a concentration of 10 g / L. The aluminum wire surface is covered with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 15μm. The concentration of K2SiF6 in the sealing solution is 15g / L, the concentration of La(NO3)3 is 5g / L, the sealing temperature is 80℃, the sealing time is 20min, and the sealing solution also contains 0.5% by mass of nano-titanium dioxide particles.

[0031] Microcapsules containing a corrosion inhibitor are evenly dispersed in the gaps between the steel core and the aluminum wire strands. The corrosion inhibitor is benzotriazole. The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 5μm, and the corrosion inhibitor content accounts for 30% of the mass of the microcapsules.

[0032] The steel core has a hollow structure, with the diameter of the hollow part being 1 / 3 of the overall outer diameter of the steel core. The hollow part is filled with damping material, which is butyl rubber, and the damping coefficient is 0.32.

[0033] The aluminum wire adopts a variable pitch stranding method. From the inner layer to the outer layer, the stranding pitch of the aluminum wire gradually increases, and the ratio of the stranding pitch of two adjacent layers of aluminum wire is 1.1.

[0034] The steel core integrates a miniature corrosion sensor and a stress sensor; the corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance, with dimensions of 0.5mm × 0.5mm × 0.2mm; The stress sensor is a fiber Bragg grating sensor with a diameter of 0.1 mm. Miniature corrosion sensors and stress sensors transmit data to the monitoring center via Bluetooth Low Energy through an ultra-miniature wireless transmission module.

[0035] The steel core surface is first coated with a Zn-Al-Mg alloy by hot-dip galvanizing at a temperature of 450°C for 3 minutes. Then, a Ni-P-SiC composite coating is deposited by chemical plating at a pH of 4.5 and a temperature of 85°C. Magnetic stirring is used at a stirring speed of 200 r / min.

[0036] When anodizing aluminum wire, the electrolyte is a 15% sulfuric acid solution, the anodic current density is 1.5A / dm², and the oxidation time is 30min.

[0037] A method for preparing corrosion-resistant steel-cored aluminum stranded wire, comprising the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:3 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

[0038] During microcapsule preparation, the reaction temperature was controlled at 60℃, the reaction time was 2h, the stirring speed was 150r / min, the emulsifier was sodium dodecyl sulfate with a mass fraction of 0.5%, and the dropping rate of urea-formaldehyde prepolymer was 1 drop / s.

[0039] The hollow steel core is made of seamless steel pipe with a wall thickness of 3mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. The damping material is preheated to 60°C before filling and filled by pressure injection at a pressure of 0.5MPa, achieving a filling rate of 95%. After filling, both ends of the steel core are sealed.

[0040] Example 2: A corrosion-resistant steel-cored aluminum stranded wire, comprising a steel core and aluminum wire stranded around the steel core; The steel core surface is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by chemical plating. The Zn-Al-Mg alloy coating has a thickness of 35 μm, wherein the mass fraction of Zn is 88%, the mass fraction of Al is 10%, and the mass fraction of Mg is 2.5%. The Ni-P-SiC composite coating has a thickness of 12 μm, and the NiSO4 content in the plating bath is [missing information]. The concentration of 6H2O is 280 g / L, and the concentration of NaH2PO2 is... The concentration of H2O is 25 g / L, and the particle size of SiC particles is 0.8 μm with a concentration of 12 g / L. The aluminum wire surface is covered with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 18μm. The concentration of K2SiF6 in the sealing solution is 18g / L, the concentration of La(NO3)3 is 6g / L, the sealing temperature is 85℃, the sealing time is 25min, and the sealing solution also contains 0.8% nano-titanium dioxide particles by mass.

[0041] Microcapsules containing a corrosion inhibitor are evenly dispersed in the gaps between the steel core and the aluminum wire strands. The corrosion inhibitor is benzotriazole. The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 8μm, and the corrosion inhibitor content accounts for 35% of the mass of the microcapsules.

[0042] The steel core has a hollow structure, with the diameter of the hollow part being 2 / 5 of the overall outer diameter of the steel core. The hollow part is filled with damping material, which is butyl rubber, and the damping coefficient is 0.35.

[0043] The aluminum wire adopts a variable pitch stranding method. From the inner layer to the outer layer, the stranding pitch of the aluminum wire gradually increases, and the ratio of the stranding pitch of two adjacent layers of aluminum wire is 1.2.

[0044] The steel core integrates a miniature corrosion sensor and a stress sensor; the corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance, with dimensions of 0.5mm × 0.5mm × 0.2mm; The stress sensor is a fiber Bragg grating sensor with a diameter of 0.1 mm. Miniature corrosion sensors and stress sensors transmit data to the monitoring center via LoRa wireless communication through an ultra-miniature wireless transmission module.

[0045] The steel core surface is first coated with a Zn-Al-Mg alloy by hot-dip galvanizing at a temperature of 460℃ for 4 minutes. Then, a Ni-P-SiC composite coating is deposited by chemical plating at a pH of 5.0 and a temperature of 90℃. Magnetic stirring is used at a stirring speed of 250 r / min.

[0046] When anodizing aluminum wire, the electrolyte is a sulfuric acid solution with a mass fraction of 18%, the anodic current density is 2.0 A / dm², and the oxidation time is 35 min.

[0047] A method for preparing corrosion-resistant steel-cored aluminum stranded wire, comprising the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:4 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

[0048] During microcapsule preparation, the reaction temperature was controlled at 65℃, the reaction time was 2.5h, the stirring speed was 200r / min, the emulsifier was sodium dodecyl sulfate with a mass fraction of 0.8%, and the dropping rate of urea-formaldehyde prepolymer was 1.5 drops / s.

[0049] The hollow steel core is made of seamless steel pipe with a wall thickness of 4mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. The damping material is preheated to 65°C before filling and filled by pressure injection at a pressure of 0.8MPa, achieving a filling rate of 98%. After filling, both ends of the steel core are sealed.

[0050] Example 3: A corrosion-resistant steel-cored aluminum stranded wire, comprising a steel core and aluminum wire stranded around the steel core; The steel core surface is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The Zn-Al-Mg alloy coating has a thickness of 40 μm, wherein the mass fraction of Zn is 90%, the mass fraction of Al is 8%, and the mass fraction of Mg is 2%. The Ni-P-SiC composite coating has a thickness of 15 μm, and the NiSO4 content in the plating bath is [missing information]. The concentration of 6H2O is 300 g / L, and the concentration of NaH2PO2 is... The concentration of H2O is 30 g / L, and the particle size of SiC is 1 μm with a concentration of 15 g / L. The aluminum wire surface is covered with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 20 μm. The concentration of K2SiF6 in the sealing solution is 20 g / L, the concentration of La(NO3)3 is 8 g / L, the sealing temperature is 90℃, the sealing time is 30 min, and the sealing solution also contains 1% by mass of nano titanium dioxide particles.

[0051] Microcapsules containing a corrosion inhibitor are evenly dispersed in the gaps between the steel core and the aluminum wire strands. The corrosion inhibitor is benzotriazole. The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 10μm, and the corrosion inhibitor content accounts for 40% of the mass of the microcapsules.

[0052] The steel core has a hollow structure, with the diameter of the hollow part being 1 / 2 of the overall outer diameter of the steel core. The hollow part is filled with damping material, which is butyl rubber, and the damping coefficient is 0.38.

[0053] The aluminum wire adopts a variable pitch stranding method. From the inner layer to the outer layer, the stranding pitch of the aluminum wire gradually increases, and the ratio of the stranding pitch of two adjacent layers of aluminum wire is 1.3.

[0054] The steel core integrates a miniature corrosion sensor and a stress sensor; the corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance, with dimensions of 0.5mm × 0.5mm × 0.2mm; The stress sensor is a fiber Bragg grating sensor with a diameter of 0.1 mm. Miniature corrosion sensors and stress sensors transmit data to the monitoring center via Bluetooth Low Energy through an ultra-miniature wireless transmission module.

[0055] The steel core surface is first coated with a Zn-Al-Mg alloy by hot-dip galvanizing at a temperature of 480℃ for 5 minutes. Then, a Ni-P-SiC composite coating is deposited by chemical plating at a pH of 5.5 and a temperature of 95℃. Magnetic stirring is used at a stirring speed of 300 r / min.

[0056] When anodizing aluminum wire, the electrolyte is a 20% sulfuric acid solution, the anodic current density is 2.5 A / dm², and the oxidation time is 40 min.

[0057] A method for preparing corrosion-resistant steel-cored aluminum stranded wire, comprising the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:5 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

[0058] During the preparation of microcapsules, the reaction temperature was controlled at 70℃, the reaction time was 3h, the stirring speed was 250r / min, the emulsifier was sodium dodecyl sulfate with a mass fraction of 1%, and the dropping rate of urea-formaldehyde prepolymer was 2 drops / s.

[0059] The hollow steel core is made of seamless steel pipe with a wall thickness of 5mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. The damping material is preheated to 70°C before filling, and then filled by pressure injection at a pressure of 1MPa, achieving a 100% filling rate. After filling, both ends of the steel core are sealed.

[0060] Comparative Example 1 differs from Example 1 in that the steel core surface is only provided with a Zn-Al-Mg alloy coating, and no Ni-P-SiC composite coating is provided.

[0061] Comparative Example 2 differs from Example 1 in that the aluminum wire surface is only anodized and not sealed.

[0062] Comparative Example 3 differs from Example 1 in that microcapsules containing corrosion inhibitors are not dispersed in the gaps between the steel core and the aluminum wire strands.

[0063] Comparative Example 4 differs from Example 1 in that the aluminum wires are stranded using a fixed pitch method, with each layer of aluminum wires having the same stranding pitch.

[0064] Performance testing: Performance tests were conducted on the corrosion-resistant steel-cored aluminum stranded wires treated according to Examples 1, 2, 3, Comparative Examples 1, 2, 3, and 4. The test items and methods are as follows: The corrosion resistance was assessed using an acidic salt spray test (pH=3.0, GB / T10125-2021), and the percentage of rusted area was calculated after 800 hours of testing. Conductivity was tested according to GB / T3048.2-2007, with a DC resistivity (Ω) at 20℃. mm² / m); Vibration fatigue resistance was tested at 10 Hz and ±2 mm amplitude, and the number of vibrations before fracture was recorded. Weather resistance was tested by ultraviolet aging test (UVB-313 lamp, irradiance 0.71W / m², 60℃ / condensation 30℃ cycle, 1000h), and coating adhesion was tested (cross-cut test, GB / T9286-1998).

[0065] The obtained test data are recorded in Table 1 below:

[0066] Performance test results show that all three examples exhibit strong corrosion resistance. The Zn-Al-Mg alloy coating serves as the basic protection, while the Ni-P-SiC composite coating further enhances the protective effect. In addition, the anodizing and sealing treatment of the aluminum wire, the role of corrosion inhibitor microcapsules in the stranding gap, and the structural stability brought about by the variable pitch stranding together construct a comprehensive corrosion protection system.

[0067] Comparative Example 1 only has a Zn-Al-Mg alloy coating on the surface of the steel core, without the support of the Ni-P-SiC composite coating. This results in insufficient protection for the steel core, making corrosion more likely to occur and spread in an acidic salt spray environment. Naturally, its corrosion resistance is not as good as that of the Example 1.

[0068] In Comparative Example 2, the aluminum wire was not sealed, and the porous structure of the anodic oxide film could not be effectively blocked. Corrosive media could easily penetrate into the aluminum wire through the pores, resulting in more severe corrosion than in the Example 2.

[0069] In Comparative Example 3, due to the lack of corrosion inhibitor microcapsules, the gaps where the steel core and aluminum wire are twisted together lose additional means of corrosion inhibition, becoming weak points for corrosion, and its corrosion resistance is not as good as that of the Example.

[0070] Comparative Example 4 uses fixed-pitch stranding, resulting in relatively poor structural stability between the aluminum wires. In corrosive environments, this structural deficiency may lead to easier accumulation of corrosive media, thereby weakening the overall corrosion resistance. Compared with the embodiment using variable-pitch stranding, the corrosion resistance is slightly inferior.

[0071] In terms of conductivity, Examples 1, 2, and 3 are all superior to Comparative Example 2. After the aluminum wire is sealed, the porous structure of the anodic oxide film is effectively filled, reducing the obstruction to current conduction. The aluminum wire in Comparative Example 2 is not sealed, and the anodic oxide film has more pores, which will have an adverse effect on current conduction, making its conductivity inferior to Examples 1, 2, and 3.

[0072] In terms of vibration fatigue resistance, Examples 1, 2, and 3 are all superior to the comparative example. The variable pitch stranding method makes the aluminum wire more uniformly stressed, reducing local stress concentration. The double coating of the steel core enhances the strength and toughness of the steel core, improves the overall fatigue resistance, and, in synergy with other structural designs, enables Examples 1, 2, and 3 to withstand more vibrations without easily breaking.

[0073] Comparative Example 4 uses fixed-pitch stranding, resulting in uneven stress on the aluminum wire during vibration. This leads to excessive local stress, causing its vibration fatigue resistance to be significantly lower than that of the Example. Comparative Example 1, with its steel core having only a single coating, suffers from insufficient fatigue strength and is more prone to fatigue damage under long-term vibration, resulting in poorer vibration fatigue resistance than the Example. Other comparative examples also show differences in vibration fatigue resistance compared to the Example, primarily due to the lack of the multiple structural optimizations and reinforcement designs found in the Example.

[0074] Regarding weather resistance, after UV aging, the coatings in Examples 1, 2, and 3 still maintained good adhesion. This is because the Ni-P-SiC composite coating on the steel core surface protected the Zn-Al-Mg alloy coating, slowed down the aging effect of UV radiation, and made it easier for the coating to bond with the steel core to decrease.

[0075] In Comparative Example 1, without the Ni-P-SiC composite coating, the Zn-Al-Mg alloy coating is directly exposed to ultraviolet radiation, which easily leads to aging, resulting in a significant decrease in coating adhesion and weather resistance that is significantly inferior to Examples 1, 2, and 3.

[0076] By comparing and analyzing the relevant data in the table, it can be seen that through multi-dimensional structural optimization and process improvement, the comprehensive performance of corrosion-resistant steel-cored aluminum stranded wire has been significantly improved. Regarding steel core protection, a dual protection system of Zn-Al-Mg alloy coating and Ni-P-SiC composite coating is adopted, which greatly enhances the corrosion resistance of the steel core in harsh corrosive environments such as acidic environments, while also improving the weather resistance and fatigue resistance of the coating. For the aluminum wire, anodizing and specific sealing liquid treatment effectively fill the oxide film pores, optimizing conductivity while ensuring corrosion resistance. A variable pitch design is adopted in the stranding structure, and microcapsules containing corrosion inhibitors are added to the gaps, further improving the overall structural stability and comprehensive corrosion protection. Therefore, it is evident that the corrosion-resistant steel-cored aluminum stranded wire and its preparation method provided by this invention have a broader market prospect and are more suitable for widespread application.

[0077] In the description of this specification, references to terms such as "an experiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that experiment or example is included in at least one experiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same experiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more experiments or examples.

[0078] The preferred experiments disclosed above are merely illustrative of the invention. These preferred experiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these experiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize it. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A corrosion-resistant steel-cored aluminum stranded wire, characterized in that, Includes a steel core and aluminum wire stranded around the steel core; The surface of the steel core is sequentially coated with a Zn-Al-Mg alloy coating formed by hot-dip galvanizing and a Ni-P-SiC composite coating deposited by electroless plating. The thickness of the Zn-Al-Mg alloy coating is 30-40 μm, wherein the mass fraction of Zn is 85%-90%, the mass fraction of Al is 8%-12%, and the mass fraction of Mg is 2%-3%. The Ni-P-SiC composite coating has a thickness of 10–15 μm, and the plating solution contains NiSO4. The concentration of 6H2O is 250-300 g / L, and NaH2PO2 The concentration of H2O is 20-30 g / L, and the particle size of SiC particles is 0.5-1 μm and the concentration is 10-15 g / L; The aluminum wire surface is provided with a porous anodic oxide film formed by anodizing and sealing treatment. The thickness of the anodic oxide film is 15-20 μm. The concentration of K2SiF6 in the sealing solution is 15-20 g / L, the concentration of La(NO3)3 is 5-8 g / L, the sealing temperature is 80-90℃, the sealing time is 20-30 min, and the sealing solution also contains 0.5%-1% by mass nano-titanium dioxide particles.

2. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, Microcapsules containing a corrosion inhibitor are uniformly dispersed in the gaps between the steel core and the aluminum wire strands. The corrosion inhibitor is benzotriazole. The microcapsules use polyurea formaldehyde as the wall material, with an average particle size of 5-10 μm, and the corrosion inhibitor content accounts for 30%-40% of the mass of the microcapsules.

3. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, The steel core has a hollow structure, with the diameter of the hollow part being 1 / 3 to 1 / 2 of the overall outer diameter of the steel core. The hollow part is filled with damping material, which is butyl rubber with a damping coefficient greater than 0.

3.

4. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, The aluminum wire adopts a variable pitch stranding method, and the stranding pitch of the aluminum wire gradually increases from the inner layer to the outer layer. The ratio of the stranding pitch of two adjacent layers of aluminum wire is 1.1 to 1.

3.

5. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, The steel core also integrates a miniature corrosion sensor and a stress sensor. The corrosion sensor is a nanomaterial sensor based on the principle of electrochemical impedance spectroscopy, with dimensions of 0.5mm × 0.5mm × 0.2mm. The stress sensor is a sensor using fiber Bragg grating technology with a diameter of 0.1 mm; The miniature corrosion sensor and stress sensor transmit data to the monitoring center via a miniature wireless transmission module using low-power Bluetooth or LoRa wireless communication.

6. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, The steel core surface is first coated with a Zn-Al-Mg alloy by hot-dip galvanizing at a temperature of 450–480°C for 3–5 min. Then, a Ni-P-SiC composite coating is deposited by chemical plating at a pH of 4.5–5.5 and a temperature of 85–95°C. A magnetic stirrer is used to stir the plating solution at a speed of 200–300 r / min.

7. The corrosion-resistant steel-cored aluminum stranded wire according to claim 1, characterized in that, When the aluminum wire is anodized, the electrolyte is a sulfuric acid solution with a mass fraction of 15% to 20%, the anodic current density is 1.5 to 2.5 A / dm², and the oxidation time is 30 to 40 min.

8. A method for preparing a corrosion-resistant steel-cored aluminum stranded wire, used to prepare the corrosion-resistant steel-cored aluminum stranded wire according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: S1: The steel core is surface treated by hot-dip galvanizing to form a Zn-Al-Mg alloy coating and electroless plating to form a Ni-P-SiC composite coating. S2: The aluminum wire is anodized and then sealed in a sealing solution; S3: Microcapsules containing corrosion inhibitors are mixed with epoxy resin binder at a mass ratio of 1:3 to 1:5 and then sprayed evenly on the surface of steel core and aluminum wire, and then stranded. The aluminum wire is stranded using a variable pitch stranding method. S4: During the stranding process, a miniature corrosion sensor and a stress sensor are embedded; S5: The hollow steel core is processed and filled with damping material, and then assembled.

9. The method for preparing a corrosion-resistant steel-cored aluminum stranded wire according to claim 8, characterized in that, During microcapsule preparation, the reaction temperature is controlled at 60–70℃, the reaction time is 2–3 h, the stirring speed is 150–250 r / min, the emulsifier is sodium dodecyl sulfate with a mass fraction of 0.5%–1%, and the urea-formaldehyde prepolymer is added at a dropping rate of 1–2 drops / s.

10. The method for preparing a corrosion-resistant steel-cored aluminum stranded wire according to claim 8, characterized in that, The hollow steel core is made of seamless steel pipe with a wall thickness of 3-5mm. During processing, dimensional accuracy and roundness are controlled to ensure concentricity. Before filling, the damping material is preheated to 60-70℃ and filled by pressure injection at a pressure of 0.5-1MPa, achieving a filling rate of 95%-98%. After filling, both ends of the steel core are sealed.

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