Production method of tinned copper-clad aluminum wire

Abstract

The invention relates to a production method of a tinned copper-clad aluminum wire, and relates to the technical field of metal material processing, and the production method comprises the following steps: S1, preparing a rare earth aluminum alloy rod; s2, surface treatment; s3, heating treatment; s4, copper strip coating and welding; s5, drawing and forming; s6, electrodeposition tin plating pretreatment; s7, electrodeposition tin plating; and S8, post-processing. According to the production method of the tinned copper-clad aluminum wire, the rare earth aluminum alloy is adopted as the aluminum core material, so that the mechanical strength and toughness of the aluminum rod are effectively improved, and the bonding performance between copper and aluminum is improved; secondly, a nano coating treatment technology is introduced, the activity of the surfaces of the aluminum rod and the copper strip is enhanced, a good foundation is provided for follow-up welding and combination, in addition, the surface of the aluminum rod is subjected to micro deformation through pulse heating treatment, the coating compactness of the copper strip is further improved, the stability and consistency of the welding process are ensured through a high-frequency induction welding technology, and the welding quality is improved. And the problems of oxidation, air holes, stripping and the like easily occurring in traditional welding are avoided.

Description

Technical Field

[0001] This invention relates to the field of metal material processing technology, specifically to a method for producing tin-plated copper-clad aluminum wire. Background Technology

[0002] Tin-plated copper-clad aluminum wire is a composite conductive material with aluminum as the core, copper as the middle layer, and tin as the outer layer. The three metals are combined together through a special process. It has the advantages of being lightweight, highly conductive, highly resistant to oxidation, and low in cost, and is widely used in electronics, communications, power, automotive and other fields.

[0003] Existing copper-clad aluminum wires are mainly manufactured using a cladding welding process, which involves cladding copper strips onto the surface of an aluminum rod and forming a metallurgical bond through welding. However, due to the large difference in thermal expansion coefficients between copper and aluminum, the easy formation of an oxide film during the welding process, and the difficulty in controlling welding parameters, the copper-aluminum interface is not tightly bonded, resulting in problems such as peeling, porosity, and high contact resistance, which seriously affect the conductivity, mechanical properties, and service life of the product.

[0004] To address the aforementioned problems, this invention proposes a novel method for producing tin-plated copper-clad aluminum wire. This method optimizes the aluminum core structure with rare-earth aluminum alloys, enhances surface activity through nano-coating, strengthens bonding through pulse heating, improves welding quality through high-frequency induction welding, and introduces plasma cleaning and closed-loop control of electrodeposition tin plating. These techniques enhance the bonding strength and stability of the copper-aluminum interface, improve conductivity, oxidation resistance, and mechanical properties, thereby solving the problems mentioned above. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for producing tin-plated copper-clad aluminum wire. This method has advantages such as optimized material formulation, improved surface treatment process, and the introduction of advanced technologies such as pulse heating and high-frequency induction welding. It solves the problems of weak copper-aluminum bonding, unstable welding quality, high interface resistance, and easy oxidation in traditional copper-clad aluminum wire manufacturing.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for producing tin-plated copper-clad aluminum wire, comprising the following steps:

[0007] S1 Preparation of rare earth aluminum alloy rods: 99.95% pure aluminum is placed in a dual-frequency induction melting furnace and heated to 700℃ to completely melt it. Then, rare earth elements (RE) and boron (B) are added alternately to the aluminum liquid. After casting, it is stirred and then cast into a rare earth aluminum alloy rod with a diameter of 15mm. Then, the rare earth aluminum alloy rod is annealed in an annealing furnace at 450℃ for 2.5 hours and drawn to a diameter of 1.0mm through multiple drawing passes.

[0008] S2 surface treatment: the aluminum rod and copper strip are respectively put into the ultrasonic cleaning tank, deionized water is used to clean at 50℃ for 12 minutes with the ultrasonic frequency of 30 kHz, then the cleaned aluminum rod and copper strip are sequentially subjected to pickling, neutralization and drying, and after drying, the surface of the dried aluminum rod and copper strip is treated with nano coating equipment;

[0009] S3 heating treatment: the aluminum rod after nano coating treatment is put into a pulse heating furnace, heated to 500℃ at a heating rate of 20℃ / min, and kept at 500℃ for 15 minutes to make the aluminum rod surface slightly deformed;

[0010] S4 copper strip cladding and welding: the high-purity copper strip is tightly wrapped around the aluminum rod after heating treatment by a wrapping machine, and then the wrapped copper strip is continuously welded using a high-frequency induction welding device;

[0011] S5 drawing forming: the copper-clad aluminum rod after welding is put into the die of the drawing machine, and the copper-clad aluminum rod is drawn to a diameter of 0.5mm through multi-pass drawing process, and the copper-clad aluminum wire is annealed online once every 2 passes;

[0012] S6 pre-treatment for electrodeposition tin plating: the drawn copper-clad aluminum wire is put into a plasma treatment device, the surface is treated with argon plasma for 10 minutes, then the copper-clad aluminum wire after plasma treatment is put into an alkali electrolysis tank, then the copper-clad aluminum wire after alkali electrolysis treatment is put into an acid electrolysis tank, and finally the copper-clad aluminum wire after acid electrolysis treatment is washed with deionized water for 2-3 minutes;

[0013] S7 electrodeposition tin plating: the pre-treated copper-clad aluminum wire is subjected to electrodeposition treatment by passing through a double-layer plating tank filled with a mixture of stannous sulfate and sulfuric acid;

[0014] S8 post-treatment: the copper-clad aluminum wire after electrodeposition tin plating is washed with deionized water for 2-3 minutes, then the copper-clad aluminum wire after secondary water washing is neutralized in an alkali neutralization tank, then the copper-clad aluminum wire after alkali neutralization treatment is washed with hot water in a hot water tank, and then the copper-clad aluminum wire after hot water washing is dried in a drying oven. After drying, the dried copper-clad aluminum wire is polished using a nano polishing device.

[0015] Further, in the process of preparing the rare earth aluminum alloy aluminum rod in step S1, the RE addition amount is 0.2% of the total weight of the aluminum liquid, and the B addition amount is 0.055% of the total weight of the aluminum liquid.

[0016] Further, in the process of surface treatment in step S2, the ultrasonic frequency is 30 kHz, the pickling solution is a 7% hydrochloric acid solution, the pickling time is 8 minutes, the neutralizing liquid is a 7% sodium carbonate solution, and the neutralizing time is 4 minutes.

[0017] Further, in the process of step S4, the tension of the copper strip during cladding is controlled at 15 N / cm2, the cladding speed is 7 m / min, the welding current is 150 A, the welding voltage is 15 V, and the welding speed is 7 m / min.

[0018] Further, in the process of step S5, the reduction ratio of each pass is controlled at 15%, the drawing speed is 7 m / min, the annealing temperature is 350°C, and the annealing time is 12 minutes.

[0019] Further, in the process of step S6, the solution for alkaline electro-treatment is a sodium hydroxide solution with a concentration of 120 g / L and a sodium carbonate solution with a concentration of 60 g / L, the reaction temperature is 70°C, the treatment time is 8 minutes, the solution for acid electro-treatment is a sulfuric acid solution with a concentration of 5%, and the water washing time is 2.5 minutes.

[0020] Further, in the process of step S7, the stannous sulfate concentration is 60 g / L, the sulfuric acid concentration is 120 g / L, the current density is controlled at 1.5 A / dm2, the walking speed is 3.5 m / min, the tin plating layer thickness is controlled at 0.02 mm, the plating bath temperature is controlled at 25°C, and the pH value is controlled at 2.0.

[0021] Further, in the process of step S8, the alkaline neutralization uses a trisodium phosphate solution with a concentration of 15 g / L at 70°C for 4 minutes, the hot water temperature for hot water cleaning is 80°C, the water washing time is 2.5 minutes, the polishing speed is 150 mm / s, and the surface roughness Ra after polishing is 0.2 μm.

[0022] Further, in the process of step S1, the rare earth element RE is at least one of lanthanum (La), cerium (Ce), and yttrium (Y), and the three elements are sequentially added to the aluminum liquid in a mass ratio of La:Ce:Y=(3-5):(1-2):(1-1.5).

[0023] Further, after step S7, the process further comprises a step of tin layer thickness on-line detection and closed-loop control of the tin-plated copper-clad aluminum wire, which specifically comprises:

[0024] 1) using an X-ray fluorescence thickness gauge to detect the tin plating layer thickness in real time;

[0025] 2) feeding the detection data back to the electrodeposition control system;

[0026] 3) the system automatically adjusts the current density and the walking speed according to the set thickness value to realize closed-loop control of the tin plating layer thickness.

[0027] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0028] 1. The production method of the tinned copper-clad aluminum wire effectively improves the mechanical strength and toughness of the aluminum rod and improves the bonding performance between copper and aluminum by using rare earth aluminum alloy as the aluminum core material. Secondly, the introduction of nano coating treatment technology enhances the activity of the aluminum rod and the surface of the copper strip, providing a good foundation for subsequent welding and bonding. In addition, pulse heating treatment causes micro deformation on the surface of the aluminum rod, further improving the cladding tightness of the copper strip, and high-frequency induction welding technology ensures the stability and consistency of the welding process, avoiding problems such as oxidation, porosity and peeling that easily occur in traditional welding.

[0029] 2. The production method of the tinned copper-clad aluminum wire thoroughly cleans the surface of the wire by plasma surface treatment, improving the adhesion of the tinned layer. Electrodeposition tinning combined with closed-loop thickness control system realizes accurate regulation and control of the thickness of the plating layer, ensuring the uniformity and consistency of the product. Finally, nano polishing technology is used for surface treatment of the finished wire, which not only improves the appearance quality, but also further enhances the oxidation resistance and welding performance. Overall, this process significantly improves the comprehensive performance of the copper-clad aluminum wire, with high conductivity, lightweight, corrosion resistance, easy welding and other advantages, suitable for electronic, communication, power and other high-end application fields. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The production method steps of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] Please refer to Figure 1 The production method of the tinned copper-clad aluminum wire in the present embodiment includes the following steps:

[0033] S1: Prepare a rare earth aluminum alloy aluminum rod: Put 99.95% pure aluminum into a double-frequency induction melting furnace and heat it to 700℃ to completely melt it. Then alternately add rare earth elements (RE) and boron (B) to the aluminum liquid, stir after pouring, and pour into a rare earth aluminum alloy rod with a diameter of 15mm. Then anneal the rare earth aluminum alloy rod in an annealing furnace at 450℃ for 2.5 hours, and draw the rare earth aluminum alloy rod to a diameter of 1.0mm through multiple passes of drawing.

[0034] S2 Surface Treatment: Place the aluminum rod and copper strip into an ultrasonic cleaning tank and use deionized water at 50°C and 30kHz for 12 minutes for ultrasonic cleaning. Then, after cleaning, the aluminum rod and copper strip are pickled, neutralized and dried in sequence. After drying, the surface of the dried aluminum rod and copper strip is treated with a nano-coating device.

[0035] S3 heat treatment: The aluminum rod with nano-coating is placed in a pulse heating furnace and heated to 500°C at a heating rate of 20°C / min. It is then held at 500°C for 15 minutes to cause slight deformation on the surface of the aluminum rod.

[0036] S4 Copper Strip Coating and Welding: High-purity copper strip is tightly wrapped onto the heat-treated aluminum rod using a coating machine, and then the coated copper strip is continuously welded using a high-frequency induction welding device.

[0037] S5 drawing process: The welded copper-clad aluminum rod is placed into the die of the drawing machine and drawn to a diameter of 0.5mm through multiple drawing processes. The copper-clad aluminum wire is annealed online every two passes.

[0038] S6 Electrodeposition Tin Plating Pretreatment: The drawn copper-clad aluminum wire is placed in a plasma treatment device and argon plasma is used to treat the surface for 10 minutes. Then, the plasma-treated copper-clad aluminum wire is placed in an alkaline electrolysis tank, and then the alkaline electrolysis-treated copper-clad aluminum wire is placed in an acid electrolysis tank. Finally, the acid electrolysis-treated copper-clad aluminum wire is placed in a deionized water tank for 2-3 minutes to wash.

[0039] S7 Electrodeposition Tin Plating: The pretreated copper-clad aluminum wire is subjected to electrodeposition treatment in a double-layer plating bath containing a mixture of stannous sulfate and sulfuric acid.

[0040] S8 Post-treatment: The copper-clad aluminum wire after electrodeposition and tin plating is placed in a deionized water bath for a second water wash of 2-3 minutes. Then, the copper-clad aluminum wire after the second water wash is placed in an alkali neutralization tank for neutralization. After the alkali neutralization treatment, the copper-clad aluminum wire is placed in a hot water bath for hot water wash. After the hot water wash, the copper-clad aluminum wire is placed in a drying oven for drying. After drying, the dried copper-clad aluminum wire is polished using a nano-polishing device.

[0041] It should be noted that:

[0042] Preparation of S1 rare earth aluminum alloy rods: By adding rare earth elements (such as La, Ce, Y) and boron, the grain structure and mechanical properties of the aluminum rods are significantly improved, enhancing their strength, toughness, and high-temperature stability, thus providing a more stable foundation for subsequent copper-aluminum bonding.

[0043] S2 surface treatment process: ultrasonic cleaning, pickling, neutralization and nano coating treatment are adopted to effectively remove surface impurities and oxide layers, improve surface activity, enhance the bonding force between copper and aluminum, and the nano coating can also improve the interface wettability and bonding stability.

[0044] S7 electrodeposition tin plating: double-layer plating tank and closed-loop control system are adopted to realize accurate control of tin plating layer thickness, ensure uniform and dense plating layer, improve product oxidation resistance, welding performance and appearance quality, and improve production efficiency and consistency.

[0045] In the process of preparing the rare earth aluminum alloy aluminum rod in step S1, the RE addition amount is 0.2% of the total weight of the aluminum liquid, and the B addition amount is 0.055% of the total weight of the aluminum liquid.

[0046] It should be noted that in step S1, by controlling the rare earth element (RE) addition amount to be 0.2% of the total weight of the aluminum liquid and the boron (B) addition amount to be 0.055%, the microstructure of the aluminum rod is accurately controlled, the strength, toughness and heat resistance of the aluminum core are significantly improved, and the bonding performance of the copper-aluminum interface is improved, providing a more stable and reliable material basis for subsequent coating and welding processes.

[0047] In the process of step S2 surface treatment, the ultrasonic frequency is 30 kHz, the pickling liquid is a 7% hydrochloric acid solution, the pickling time is 8 minutes, the neutralizing liquid is a 7% sodium carbonate solution, and the neutralizing time is 4 minutes.

[0048] It should be noted that step S2 adopts a combination of 30 kHz ultrasonic cleaning, 7% hydrochloric acid pickling for 8 minutes and 7% sodium carbonate neutralization for 4 minutes, effectively removing oil stains, oxide layers and impurities on the surface of the aluminum rod and copper strip, improving the surface cleanliness and activity, providing good interface conditions for subsequent nano coating treatment and copper-aluminum bonding, thereby enhancing the bonding strength and stability of product quality.

[0049] In the process of step S4 copper strip coating and welding, the tension of the copper strip during coating is controlled at 15 N / cm², the coating speed is 7 m / min, the welding current is 150 A, the welding voltage is 15 V, and the welding speed is 7 m / min.

[0050] It should be noted that step S4 controls the copper strip coating tension at 15 N / cm², sets the coating speed to 7 m / min, and adopts high-frequency induction welding parameters of 150 A welding current, 15 V welding voltage and 7 m / min welding speed, realizing the close fit and stable welding between the copper strip and the aluminum rod, effectively avoiding defects such as coating relaxation and virtual welding, and significantly improving the bonding strength of the copper-aluminum interface and the welding consistency.

[0051] In the step S5, the diameter reduction rate of each pass is controlled to be 15%, the drawing speed is 7 m / min, and the annealing temperature is 350 DEG C and the annealing time is 12 minutes.

[0052] It should be noted that the step S5 controls the diameter reduction rate of each pass to be 15%, sets the drawing speed to be 7 m / min, and cooperates with the online annealing treatment of 350 DEG C x 12 minutes, effectively reduces the work hardening tendency, maintains the plasticity and toughness of the material, ensures the uniformity of the diameter size and the surface quality, and improves the combination stability of the copper-aluminum interface, thereby providing a good foundation for the subsequent tinning process.

[0053] In the step S6, the alkali electrolytic treatment solution is a 120 g / L sodium hydroxide solution and a 60 g / L sodium carbonate solution, the reaction temperature is 70 DEG C, the treatment time is 8 minutes, the acid electrolytic treatment solution is a 5% sulfuric acid solution, and the water washing time is 2.5 minutes.

[0054] It should be noted that the step S6 adopts the 120 g / L sodium hydroxide and 60 g / L sodium carbonate mixed solution to perform the alkali electrolytic treatment on the copper-clad aluminum wire at 70 DEG C for 8 minutes, then performs the acid washing with the 5% sulfuric acid, and cooperates with the 2.5 minutes of deionized water washing, effectively removes the surface oxide layer, oil stains and residual impurities, significantly improves the cleanliness and activity of the wire surface, provides a good adhesion foundation for the subsequent electrodeposition tinning, and ensures that the plated layer is uniform and dense, and firmly combined.

[0055] In the step S7, the stannous sulfate concentration is 60 g / L, the sulfuric acid concentration is 120 g / L, the current density is controlled to be 1.5 A / dm2, the wire speed is 3.5 m / min, the tinning layer thickness is controlled to be 0.02 mm, and the plating bath temperature is controlled to be 25 DEG C and the pH value is controlled to be 2.0.

[0056] It should be noted that the step S7 controls the stannous sulfate concentration to be 60 g / L and the sulfuric acid concentration to be 120 g / L, cooperates with the current density of 1.5 A / dm2, the wire speed of 3.5 m / min, the plating bath temperature of 25 DEG C, and the precise process parameters of pH 2.0, realizes the uniform and dense tinning layer with the thickness of 0.02 mm, and the parameter combination effectively improves the stability and deposition efficiency of the tinning process, ensures that the plated layer has consistent thickness and strong adhesion, thereby enhancing the oxidation resistance, welding performance and overall appearance quality of the wire.

[0057] In the process of step S8 post-treatment, the alkali neutralization is performed using a 15 g / L concentration of trisodium phosphate solution at 70°C for 4 minutes, the hot water temperature for washing is 80°C, the washing time is 2.5 minutes, and the polishing speed is 150 mm / s, and the surface roughness Ra after polishing is 0.2 μm.

[0058] It should be noted that in the process of step S8 post-treatment, the alkali neutralization is performed using a 15 g / L concentration of trisodium phosphate solution at 70°C for 4 minutes, effectively removing the residual acidic substances on the surface of the tin plating layer, ensuring the stability and corrosion resistance of the plating layer; then washing in 80°C hot water for 2.5 minutes further removes the surface residues, ensuring the purity of the plating layer, and finally through the nano-polishing process with a polishing speed of 150 mm / s, the surface roughness of the tin-coated copper-clad aluminum wire reaches Ra 0.2 μm, significantly improving the surface finish and flatness, enhancing the oxidation resistance and welding performance of the product, and ensuring the output of high-quality finished products. This series of fine processing not only optimizes the quality of the tin plating layer, but also improves the overall reliability and market competitiveness of the product.

[0059] In the process of step S1, the rare earth elements RE are at least one of lanthanum (La), cerium (Ce) and yttrium (Y), and the three elements are added to the aluminum liquid in a mass ratio of La:Ce:Y=(3-5):(1-2):(1-1.5).

[0060] It should be noted that in the process of step S1, the rare earth elements RE are at least one of lanthanum (La), cerium (Ce) and yttrium (Y), and the three elements are added to the aluminum liquid in a mass ratio of La:Ce:Y=(3-5):(1-2):(1-1.5). This specific ratio of rare earth element doping significantly optimizes the grain structure and performance of the aluminum rod, which not only refines the grain, improves the mechanical strength and electrical conductivity of the aluminum rod, but also enhances its corrosion resistance and thermal stability, thereby providing a better substrate for subsequent copper coating and welding processes, ensuring that the final tin-coated copper-clad aluminum wire has excellent overall performance and reliability, effectively solving the balance problem between high strength and high conductivity of traditional aluminum rods, and improving the overall performance of the product.

[0061] After step S7 electro-deposition of tin, the process further includes the step of on-line detection and closed-loop control of the tin layer thickness of the tin-coated copper-clad aluminum wire, which specifically includes:

[0062] 1) Real-time detection of the tin layer thickness using an X-ray fluorescence thickness gauge;

[0063] 2) Feedback of the detection data to the electro-deposition control system;

[0064] 3) The system automatically adjusts the current density and the wire speed according to the set thickness value to realize closed-loop control of the tin plating layer thickness.

[0065] It should be noted that after the electro-deposition tin plating in step S7, the uniformity and consistency of the tin plating layer are significantly improved by introducing the tin layer thickness online detection and closed-loop control step. Specifically, the X-ray fluorescence thickness gauge is used to detect the tin plating layer thickness in real time, and the detection data is fed back to the electro-deposition control system. The system automatically adjusts the current density and the wire speed according to the set thickness value to realize closed-loop control of the tin plating layer thickness, which not only ensures the accurate control of the tin plating layer thickness, but also effectively avoids the thickness unevenness problem that may occur in the traditional process, improves the quality and reliability of the product, and meets the strict requirements of high-end applications on the consistency of the plating layer. This intelligent closed-loop control system significantly improves the production efficiency and the consistency of the product, and enhances the market competitiveness.

[0066] In the present embodiment, a series of innovative process steps are used to significantly improve the performance and quality of the product. First, the grain structure of the aluminum rod is optimized by using rare earth elements, and the firm metallurgical bonding between copper and aluminum is achieved by pulse heating and high-frequency induction welding technology, solving the problem of loose interface bonding in the traditional process. Then, the surface wettability and bonding force are enhanced by ultrasonic cleaning, chemical etching and nano coating treatment, and the uniform deformation and ductility of the wire are ensured by multi-pass drawing and online annealing. During the electro-deposition tin plating process, real-time detection is performed by the X-ray fluorescence thickness gauge and the detection data is fed back to the control system to realize closed-loop control of the tin plating layer thickness, ensuring the uniformity and consistency of the plating layer. Finally, the oxidation resistance and surface finish of the product are further improved by alkali neutralization, hot water cleaning and nano polishing post-processing. The tin-plated copper-clad aluminum wire produced by this method has excellent electrical conductivity, mechanical strength and corrosion resistance, and is suitable for multiple high-end application fields such as power transmission, communication engineering, electronic products and automobile manufacturing, significantly improving the market competitiveness and reliability of the product.

[0067] It should be noted that in this document, the terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or equipment including the element.

[0068] While embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the production of tinned copper clad aluminium wire characterised in that: The method comprises the following steps: S1: preparing a rare earth aluminum alloy aluminum rod: placing refined aluminum with a content of 99.95% into a double-frequency induction melting furnace, heating to 700 DEG C to completely melt, then alternately adding rare earth elements (RE) and boron (B) in the aluminum liquid, after pouring, stirring and pouring into a rare earth aluminum alloy rod with a diameter of 15 mm, then annealing the rare earth aluminum alloy rod in an annealing furnace at 450 DEG C for 2.5 hours, and through multiple drawing, the rare earth aluminum alloy rod is drawn to a diameter of 1.0 mm; S2: surface treatment: placing the aluminum rod and the copper strip into an ultrasonic cleaning tank respectively, using deionized water to clean at 50 DEG C for 12 minutes with a frequency of 30 kHz, then sequentially performing pickling, neutralization and drying on the cleaned aluminum rod and copper strip, and then using a nano coating device to perform nano coating treatment on the surface of the dried aluminum rod and copper strip; S3: heating treatment: placing the aluminum rod after nano coating treatment into a pulse heating furnace, heating to 500 DEG C at a heating rate of 20 DEG C / min, and keeping at 500 DEG C for 15 minutes to make the aluminum rod surface slightly deformed; S4: copper strip cladding and welding: tightly cladding the high-purity copper strip on the aluminum rod after heating treatment by using a cladding machine, and then continuously welding the cladded copper strip by using a high-frequency induction welding device; S5: drawing forming: placing the copper-clad aluminum rod after welding into a die of a drawing machine, and drawing the copper-clad aluminum rod to a diameter of 0.5 mm through a multi-pass drawing process, and performing online annealing treatment on the copper-clad aluminum wire every 2 passes; S6: pretreatment before electrodeposition tin plating: placing the drawn copper-clad aluminum wire into a plasma treatment device, treating the surface with argon plasma for 10 min, then placing the copper-clad aluminum wire after plasma treatment into an alkali electrolytic tank, then placing the copper-clad aluminum wire after alkali electrolytic treatment into an acid electrolytic tank, and finally placing the copper-clad aluminum wire after acid electrolytic treatment into a deionized water tank for water washing for 2-3 min; S7: electrodeposition tin plating: placing the pretreated copper-clad aluminum wire into a double-layer plating tank filled with a mixture of stannous sulfate and sulfuric acid for electrodeposition treatment; S8: post-treatment: placing the copper-clad aluminum wire after electrodeposition tin plating into a deionized water tank for secondary water washing for 2-3 min, then placing the copper-clad aluminum wire after secondary water washing into an alkali neutralization tank for neutralization, then placing the copper-clad aluminum wire after alkali neutralization treatment into a hot water tank for hot water washing, then placing the copper-clad aluminum wire after hot water washing into a drying box for drying, and then using a nano polishing device to polish the dried copper-clad aluminum wire.

2. A process for producing a tinned copper-clad aluminium wire as claimed in claim 1, characterized in that: In the process of step S1 of preparing the rare earth aluminum alloy aluminum rod, the RE addition amount is 0.2% of the total weight of the aluminum liquid, and the B addition amount is 0.055% of the total weight of the aluminum liquid.

3. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the process of step S2 of surface treatment, the ultrasonic frequency is 30 kHz, the pickling solution is a hydrochloric acid solution with a concentration of 7%, the pickling time is 8 min, the neutralization liquid is a sodium carbonate solution with a concentration of 7%, and the neutralization time is 4 min.

4. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S4, the tension of the copper strip is controlled at 15 N / cm2 during the cladding process, the cladding speed is 7 m / min, the welding current is 150 A, the welding voltage is 15 V, and the welding speed is 7 m / min.

5. The process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S5, the reduction rate of each pass is controlled at 15%, the drawing speed is 7 m / min, the annealing temperature is 350℃, and the annealing time is 12 minutes.

6. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S6, the alkaline solution for the alkaline treatment is a sodium hydroxide solution with a concentration of 120 g / L and a sodium carbonate solution with a concentration of 60 g / L, the reaction temperature is 70℃, the treatment time is 8 minutes, the acid solution for the acid treatment is a sulfuric acid solution with a concentration of 5%, and the water washing time is 2.5 minutes.

7. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S7, the stannous sulfate concentration is 60 g / L, the sulfuric acid concentration is 120 g / L, the current density is controlled at 1.5 A / dm2, the walking speed is 3.5 m / min, the tin layer thickness is controlled at 0.02 mm, the plating bath temperature is controlled at 25℃, and the pH value is controlled at 2.

0.

8. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S8, the alkaline neutralization uses a trisodium phosphate solution with a concentration of 15 g / L at 70℃ for 4 minutes, the hot water temperature for the hot water cleaning is 80℃, the water washing time is 2.5 minutes, the polishing speed is 150 mm / s, and the surface roughness Ra after polishing is 0.2 μm.

9. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: In the step S1, the rare earth element RE is at least one of lanthanum (La), cerium (Ce), and yttrium (Y), and the three elements are added to the aluminum liquid in a mass ratio of La:Ce:Y=(3-5):(1-2):(1-1.5).

10. A process for producing a tinned copper clad aluminium wire as claimed in claim 1, wherein: After the step S7, the method further includes a step of tin layer thickness on-line detection and closed-loop control of the tinned copper clad aluminum wire, which specifically includes: 1) using an X-ray fluorescence thickness gauge to detect the tin layer thickness in real time; 2) feeding the detection data to the electrodeposition control system; 3) automatically adjusting the current density and the walking speed according to the set thickness value to realize closed-loop control of the tin layer thickness.

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