Preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire

Abstract

The present invention relates to a preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire, and relates to the technical field of welding materials. The preparation process of the high-strength gas shielded welding wire includes the following steps: pretreatment, preparation of a first copper layer by electroless copper plating, preparation of a second copper layer by electroplating copper, sealing and post-treatment. The first copper plating solution includes copper sulfate, sodium hypophosphite, sodium hydroxide, sodium dodecylbenzenesulfonate, and a stabilizer. The stabilizer includes 2,2'-bipyridine and thiourea with a mass ratio of 2-3:1; the second copper plating solution includes copper sulfate, sodium methylsulfonate, boric acid-triethanolamine buffer solution, potassium perfluorooctanesulfonate, and an additive. The additive includes polyaspartic acid and sulfobetaine; the sealing solution includes acrylic emulsion and aziridine. The high-strength gas shielded welding wire obtained by the preparation process of the present invention can obtain an ideal, uniform and well-adhered copper plating layer thickness, ensuring the stability of various properties of the high-strength gas shielded welding wire.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and particularly to a preparation process of a high-strength gas shielded welding wire, the high-strength gas shielded welding wire and its application. Background Art

[0002] With the development of automatic welding, gas shielded copper-plated solid welding wires are suitable for all-position welding, and have the advantages of high welding speed and high deposition efficiency. They are widely used in the fields of automobile industry, shipbuilding industry, construction industry, etc. in China. With the rapid growth of the application of gas shielded welding wires in different fields, in order to ensure the performance of the welding wires, the welding wires are generally copper-plated on their surfaces. In the traditional electroplating copper process for welding wires, the main components of the copper plating solution are copper sulfate (CuSO4) and sulfuric acid (H2SO4). Copper sulfate provides Cu 2+ ions to the solution and is the replenishment source of metallic copper. Sulfuric acid plays two roles in the copper plating process: one is to activate the surface of the welding wire; the other is to stabilize the plating solution and prevent the hydrolysis of copper sulfate to produce precipitation. In addition to the main chemical components in the copper plating solution, sometimes a brightener NaCl or some other additives that can improve the surface brightness of the welding wire are added.

[0003] The Chinese patent application with the publication number of CN102618857A discloses a process method for electroplating copper on welding wires. The process steps are as follows: first, the ER50-6 welding wire to be processed is subjected to surface degreasing and activation treatment; then the surface-treated welding wire is put into the copper plating solution for electroplating copper treatment; then the copper-plated welding wire is washed with water and then passivated and polished; finally, the passivated and polished welding wire is dried and then coiled and packaged.

[0004] The copper plating quality using the above process is good, and the coating combination is reliable quickly; the copper plating of the welding wire is easy to perform on a copper plating production line in a flow operation. The wire feeding speed of the copper-plated welding wire can reach 1-2 m / s, the production efficiency is greatly improved, and the quality is stable and the energy consumption is low. The copper layer obtained by the electroplating copper process is relatively thin, generally 0.1-0.5 μm, and it is relatively easy to obtain excellent copper plating adhesion. However, during the continuous production process, the Cu 2+ in the copper plating solution is consumed, and the concentration shows a downward trend. Fe 2+ is continuously generated on the surface of the welding wire and dissolves into the copper plating solution. The Fe 2+As the concentration gradually increases, it is not conducive to obtaining a uniform copper plating layer quality. Moreover, electroless copper plating utilizes the strength of metal activity to obtain a copper layer through chemical displacement reactions. Therefore, for welding wires containing some inactive alloy elements, it is not easy to obtain an ideal copper plating layer thickness. To ensure the stability of properties such as electrical conductivity, wire feeding performance, and corrosion resistance of the welding wire, a uniform plating layer needs to be formed on the surface of the gas shielded welding wire. If the copper plating on the surface of the gas shielded welding wire is uneven or does not reach the ideal thickness, the friction between the welding wire and the contact tip inside the contact tip during welding will cause tiny copper flakes to fall off from the surface of the welding wire and accumulate in the contact tip, which is called "contact tip blockage". This contact tip blockage will lead to unstable arcs and unstable wire feeding, and at the same time increase the spatter amount.

[0005] The Chinese invention patent application with the publication number CN118773685A discloses a high-speed copper plating solution for solid welding wires and its copper plating process. The high-speed copper plating solution includes 32 - 46 parts of water-soluble copper salt, 5 - 8 parts of brightener, 20 - 27 parts of leveling agent, 4 - 12 parts of additive, 3 - 6 parts of inhibitor, 2 - 5 parts of accelerator, and 900 parts of deionized water. The additive is a mixture of sodium 2-thiazolinyl polydithiopropane sulfonate and sodium N,N-dimethyldithiocarbamidopropane sulfonate. The accelerator is selected from one or two of potassium piperazine-1,4-bis(dithiocarboxylate) or sodium 2,3-dimercaptopropanesulfonate. By optimizing various parameters of the electroplating process and the formula of the copper plating solution, the electroplating rate, tensile strength, and corrosion resistance of the welding wire are significantly improved.

[0006] Using the above preparation process, copper ions (Cu 2+ ) can gain electrons and deposit on the surface of the welding wire, and a relatively thick copper layer can be obtained. However, electroplating copper is accompanied by a slight degree of chemical displacement reaction, which has an adverse effect on the adhesion of the copper plating. When Fe on the surface layer of the welding wire loses electrons and precipitates Fe 2+ , and reacts with Cu 2+ on the surface layer through a displacement reaction to generate "displacement copper". Then, Fe below the surface layer will also lose electrons and precipitate Fe 2+ At this time, due to the electrochemical reaction on the surface of the welding wire, Cu 2+ has gained electrons and precipitated "electrical copper", covering the surface of the welding wire, making Cu 2+ unable to reach below the surface layer to complete the displacement reaction, and thus "holes" will be formed at the position where Fe 2+ precipitates.

[0007] In summary, it is not easy to obtain a copper plating layer with an ideal thickness, uniform stability, and good adhesion using the electroless copper plating process or the electroplating copper process, which is likely to cause instability in multiple properties of the gas shielded welding wire. Summary of the Invention

[0008] To solve the above problems, the present invention provides a preparation process for a high-strength gas shielded welding wire and the high-strength gas shielded welding wire. The high-strength gas shielded welding wire prepared by using the preparation process of the present invention can obtain an ideal, uniform and well-adhering copper plating layer thickness, ensuring the stability of various properties of the high-strength gas shielded welding wire.

[0009] In a first aspect, the present invention provides a preparation process for a high-strength gas shielded welding wire. The preparation process for the high-strength gas shielded welding wire includes the following steps:

[0010] Preparing a first copper layer by electroless copper plating: Placing a first welding wire into a first copper plating solution, carrying out electroless electroplating for 3 - 5 minutes under the conditions of a temperature of 54 - 56°C and a rotation speed of 3 - 5 m / min to form a first copper layer on the surface of the first welding wire. After immersing the first copper layer in a 1% silane coupling agent for 3 - 5 minutes, drying it at a temperature of 55 - 60°C to obtain a second welding wire;

[0011] Preparing a second copper layer by electroplating copper: Using a second copper plating solution to electroplate copper on the second welding wire at a current density of 13 - 15 A / dm 2 , and an electroplating temperature of 40 - 45°C to form a second copper layer on the surface of the second welding wire, thereby obtaining the high-strength gas shielded welding wire;

[0012] By mass, the first copper plating solution includes 15 - 20 parts of copper sulfate, 30 - 40 parts of sodium hypophosphite, 15 - 18 parts of sodium hydroxide, 0.01 - 0.05 parts of sodium dodecylbenzenesulfonate, 0.05 - 0.1 part of a stabilizer, and the stabilizer includes 2,2'-bipyridine and thiourea with a mass ratio of 2 - 3:1; the second copper plating solution includes 30 - 50 parts of copper sulfate, 60 - 100 parts of sodium methylsulfonate, 15 - 25 parts of boric acid - triethanolamine buffer solution, 0.1 - 0.5 part of potassium perfluorooctanesulfonate, 0.5 - 1 part of an additive, and the additive includes polyaspartic acid and sulfobetaine with a mass ratio of 1 - 1.5:1;

[0013] The mass ratio of the first copper plating solution to the second copper plating solution is 1:1.5 - 2.

[0014] In the above technical solution, copper sulfate in the first copper plating solution provides a copper source, and sodium hypophosphite acts as a reducing agent, providing electrons and releasing active H under alkaline conditions - , reducing Cu 2+The metal is copper, sodium hydroxide is used as a pH buffer to adjust alkalinity and maintain the reaction environment, sodium dodecylbenzenesulfonate is used as a wetting agent to reduce the surface tension of the first copper plating solution, enabling the solution to spread rapidly into micropores or grooves, improving the uniformity of the coverage of the first copper plating solution, and at the same time adsorbing on the surface of the wire rod to displace residual bubbles and prevent gas retention from forming pores. 2,2'-Bipyridine can inhibit side reactions, prevent the spontaneous decomposition of the first copper plating solution, extend the service life of the first copper plating solution, inhibit the formation of cuprous oxide (Cu2O), and avoid the brittleness and decreased conductivity of the coating due to inclusion of oxides. Thiourea can cooperate with 2,2'-bipyridine to stabilize the first copper plating solution, reduce the porosity of the first copper layer, and improve the surface finish of the first copper layer.

[0015] The first copper layer is immersed in a silane coupling agent. The siloxane group (Si-O-) in the silane coupling agent hydrolyzes with the metallic copper on the surface of the first copper layer to form chemical bonds, and the other end of the organic functional group (such as epoxy group, amino group) binds to the second copper plating solution, achieving the "molecular bridge" connection of the inorganic-organic interface, enhancing the chemical bonding strength between the second copper layer and the first copper layer, reducing the peeling risk caused by physical stress or environmental corrosion. At the same time, treatment with the silane coupling agent can reduce the surface energy of the first copper layer, making it easier to wet with the second copper plating solution and reducing interface defects (such as bubbles, microcracks), thereby improving adhesion and uniformity.

[0016] Copper sulfate in the second copper plating solution provides a copper source, and sodium methylsulfonate is used as a conductive salt. Sodium methylsulfonate is completely ionized in water to generate Na + and CH3SO3 - ions, significantly increasing the conductivity of the plating solution and improving the coating coverage ability in low current density areas such as deep holes and grooves. The CH3SO3 - ions can adsorb on the cathode surface to form a dynamic barrier, increasing the hydrogen evolution overpotential, thereby reducing hydrogen generation and avoiding the looseness of the coating caused by hydrogen retention. The CH3SO3 - can also form [Cu(CH3SO3)] 2+ with Cu + , moderately slowing down the reduction rate of Cu 2+ and promoting grain refinement. Potassium perfluorooctanesulfonate is used as a wetting agent. The perfluorooctyl chain in it has an extremely low surface energy, and its sulfonic acid group (-SO3 - ) is directionally adsorbed on the surface of the first copper layer, reducing the surface tension of the second copper plating solution, enabling the solution to spread rapidly into micropores or grooves, improving the uniformity of the coverage of the second copper plating solution, and at the same time can form a monolayer on the cathode surface to block the retention of hydrogen bubbles. Polyaspartic acid forms a stable chelate with Cu²⁺ through carboxyl and amino functional groups, inhibits the hydrolysis and abnormal deposition of free copper ions, extends the service life of the plating solution, forms a physical barrier film on the coating surface, and inhibits Cl- , the penetration of corrosive media such as O2, delays the oxidation reaction of copper, can also reduce the risk of spontaneous decomposition of the second copper plating, and maintain the uniform dispersion of metal ions during the electroplating process. As an amphoteric surfactant, sulfobetaine can reduce the surface tension of the second copper plating solution, enhance the wettability of the electrode / second copper plating solution interface, reduce the defects of the second copper layer caused by bubble attachment, and improve the uniformity of copper deposition by adsorbing on the electrode surface to form a uniform electric field distribution. It preferentially adsorbs on the micro-protrusions of the substrate, inhibits local over-deposition, realizes the surface leveling of the second copper layer, and improves the brightness. The synergistic effect of sulfobetaine and polyaspartic acid can further refine the grains and reduce the roughness of the second copper layer.

[0017] Electroless copper plating can achieve complete coverage on the surface of the wire rod with many surface grooves and microcracks after drawing through autocatalytic reaction. The electroless copper plating layer as the bottom layer can ensure the uniform growth of the subsequent electroplated copper layer, avoid missing plating caused by uneven current distribution during electroplating, and form a uniform copper layer. And electroplated copper realizes rapid thickening on the basis of the electroless copper plating thin layer. The electroplated copper layer further enhances the surface hardness and wear resistance on the basis of the electroless copper plating layer, prolongs the service life of the workpiece in the friction environment, improves the arc stability and wire feeding stability of the gas shielded welding wire, and at the same time avoids a large amount of spatter.

[0018] Optionally, the preparation method of the first welding wire is: draw the wire rod to a diameter of 1.0 - 1.2 mm and a surface roughness of Ra ≤ 0.6 μm, then use a neutral enzyme cleaning agent to clean the wire rod for 10 - 15 min at a temperature of 55 - 60 °C and a pH of 7.0 - 7.5 to remove surface grease, then acidify the wire rod with a mixed solution of citric acid and hydrogen peroxide with a mass ratio of 2 - 3:1 under ultrasonic assistance, and finally use Pd - Sn colloid for catalysis to obtain the first welding wire.

[0019] In the above technical solution, Pd - Sn colloid is adsorbed on the surface of the wire rod through van der Waals force to form high - density catalytic sites, which promotes the grain refinement of the first copper layer formed by electroless copper plating, significantly reduces the porosity, and can also accelerate the speed of electroless copper plating.

[0020] Optionally, the preparation process of the high - strength gas shielded welding wire further includes a sealing and post - treatment step, and the sealing and post - treatment step is: put the high - strength gas shielded welding wire into a sealing solution and soak it at a temperature of 75 - 80 °C for 2 - 3 min to form a film quickly, and then passivate and dry it; the sealing solution includes acrylic emulsion and aziridine with a mass ratio of 10 - 20:1.

[0021] In the above technical solution, the acrylic emulsion and aziridine in the sealing solution cross - link to form an acrylic resin polymer, and the polymer forms a film on the surface of the copper layer, which can seal the pores. The carboxyl groups contained in the resin can coordinate with metal ions and enhance the adsorption force with the copper layer.

[0022] Optionally, the first copper plating solution comprises 30 - 40 parts by mass of a first composite complexing agent, and the first composite complexing agent comprises sodium citrate and potassium sodium tartrate with a mass ratio of 1 - 1.5:1.

[0023] In the above technical solution, sodium citrate can form a stable complex [Cu(C6H5O7)] with Cu through carboxyl and hydroxyl groups 2+ to prevent the hydrolysis or precipitation of copper ions, ensure the uniform release of copper ions in the plating solution, improve the throwing power, and at the same time, sodium citrate is environmentally friendly and non-toxic. Potassium sodium tartrate combines with copper ions in an alkaline solution to form a soluble complex, avoiding the formation of copper hydroxide precipitation and maintaining the stability of the plating solution. 3-

[0024] Optionally, the first copper plating solution comprises 0.1 - 0.2 parts by mass of carboxylated carbon nanotubes, and the carboxylated carbon nanotubes are obtained by oxidizing carbon nanotubes in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1.

[0025] In the above technical solution, the carboxyl functional groups (-COOH) introduced on the surface of the carboxylated carbon nanotubes significantly enhance the hydrophilicity of the first copper plating solution, making it more easily and uniformly dispersed in the first copper plating solution, avoiding the problem of uneven plating caused by hydrophobic aggregation. The carboxyl functional groups maintain the stable suspension state of the carbon nanotubes in the plating solution through electrostatic repulsion, ensuring their uniform distribution in the plating layer. The surface active sites of the carboxylated carbon nanotubes can form coordination bonds with copper ions, promoting the chemical combination of the copper plating layer and the carbon nanotubes, and enhancing the overall mechanical properties of the plating layer. Coating a copper layer on the surface of the carbon nanotubes by electroless copper plating can improve the wettability between the carbon nanotubes and the metal matrix, reduce interface defects, and enhance the bonding strength of the plating layer. As a conductive enhancer, the carboxylated carbon nanotubes can construct a three-dimensional conductive network in the plating solution, accelerate the reduction process of copper ions, and improve the deposition rate and compactness of the plating layer. The carboxyl functional groups can adsorb copper ions as active sites, optimize the distribution of copper ions in the plating solution, inhibit the aggregation of copper particles, and refine the grains of the plating layer.

[0026] Optionally, the second copper plating solution comprises 15 - 25 parts by mass of a second composite complexing agent, and the second composite complexing agent comprises sodium gluconate and aminosulfonic acid with a mass ratio of 1.2 - 1.5:1.

[0027] In the above technical solution, sodium gluconate can form a stable [Cu(C6H 2+ O7)] with Cu 11 O7)] 2-Complexes can prevent the hydrolysis or abnormal deposition of copper ions in the second copper plating solution, maintain the uniformity of the second copper plating solution, and can also adjust the pH value of the second copper plating solution, maintain the acid-base environment of the electroplating reaction, improve the uniformity of the coating crystallization, still maintain the corrosion inhibition performance under high-temperature conditions, reduce the porosity of the coating, and enhance the corrosion resistance. Sulfamic acid can promote the grain refinement of the second copper layer, form a dense and ductile copper coating, reduce the internal stress of the coating, adsorb on the metal surface in the second copper plating solution, inhibit dendrite growth, and improve the uniformity and bonding strength of the second copper layer. Sodium gluconate can also synergistically enhance the throwing power of the second copper plating solution with sodium methyl sulfonate, improving the thickness uniformity of the second copper layer.

[0028] Optionally, the second copper plating solution includes 0.1 - 0.2 parts by mass of nitrogen-doped carbon quantum dots, and the nitrogen-doped carbon quantum dots are prepared by a hydrothermal reaction using citric acid as a carbon source and ethylenediamine as a nitrogen source.

[0029] In the above technical solution, the surface of the nitrogen-doped carbon quantum dots is rich in functional groups such as amino (-NH2) and carboxyl (-COOH), which can form stable coordination complexes with Cu 2+ to inhibit the hydrolysis or abnormal deposition of free copper ions, maintain the uniformity of the second copper plating solution. The high specific surface area and hydrophilicity of the nitrogen-doped carbon quantum dots can adsorb copper particles, prevent agglomeration and improve the dispersion stability of the plating solution, reduce the porosity of the coating. The nitrogen-doping characteristics endow it with electrocatalytic activity, which can reduce the activation energy of the copper ion reduction reaction, accelerate the electrochemical deposition rate, and improve the electroplating efficiency. Through the optimization of interfacial charge transfer, it promotes the uniform nucleation of copper crystal nuclei and forms a dense coating. The nitrogen-doped carbon quantum dots adsorbed on the electrode surface can serve as nucleation sites, inhibit the coarsening of copper grains, and improve the hardness and wear resistance of the coating. By surface adsorption, it reduces the internal stress of the coating and reduces the risk of cracks and warping.

[0030] In a second aspect, the present invention provides a high-strength gas shielded welding wire, which includes a wire rod and a copper plating layer, and the copper plating layer includes a first copper layer and a second copper layer.

[0031] Optionally, the thickness of the first copper layer is 1 - 3 μm, and the thickness of the second copper layer is 5 - 15 μm.

[0032] In a third aspect, the present invention provides a high-strength gas shielded welding wire prepared by the preparation process of a high-strength gas shielded welding wire and its application in the petrochemical industry, shipbuilding industry, aerospace industry, food machinery and medical device manufacturing industry, and energy storage and transportation equipment industry.

[0033] In summary, the present invention includes at least one of the following beneficial technical effects:

[0034] By immersing the first copper layer in a silane coupling agent, the silicon-oxygen groups (Si-O-) in the silane coupling agent hydrolyze with the metallic copper on the surface of the first copper layer to form chemical bonds, while the other end of the organic functional groups (such as epoxy groups, amino groups) binds to the second copper plating solution, realizing the "molecular bridge" connection of the inorganic-organic interface, enhancing the chemical bonding strength between the second copper layer and the first copper layer, reducing the peeling risk caused by physical stress or environmental corrosion. At the same time, the use of a silane coupling agent treatment can reduce the surface energy of the first copper layer, making it easier to wet with the second copper plating solution, reducing interface defects, thereby improving the adhesion and uniformity of the plating layer.

[0035] By combining electroless copper plating process and electroplating copper process, electroless copper plating can achieve complete coverage on the surface of the wire rod with many surface grooves and microcracks after drawing through autocatalytic reaction. The electroless copper plating layer as the bottom layer can ensure the uniform growth of the subsequent electroplated copper layer, avoiding missing plating caused by uneven current distribution during electroplating, and forming a uniform copper layer. While electroplating copper realizes rapid thickening on the basis of the electroless copper plating thin layer, the electroplated copper layer further enhances the surface hardness and wear resistance on the basis of the electroless copper plating layer, prolonging the service life of the workpiece in a friction environment, improving the arc stability and wire feeding stability of the gas shielded welding wire, and avoiding a large amount of spatter at the same time. Specific embodiments

[0036] The present invention will be further described in detail below with reference to the embodiments.

[0037] The materials used in the following embodiments can all be obtained through market purchase.

[0038] Embodiment 1: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0039] S1. Prepare the first copper layer by electroless copper plating: Put the first welding wire into the first copper plating solution and perform electroless electroplating for 5 minutes at a temperature of 55°C and a rotation speed of 5 m / min to form the first copper layer on the surface of the first welding wire. Immerse the first copper layer in a 1% silane coupling agent for 5 minutes and then dry it at 60°C to obtain the second welding wire;

[0040] S2. Prepare the second copper layer by electroplating copper: Use the second copper plating solution to electroplate copper on the second welding wire at a current density of 15 A / dm 2 , and the electroplating temperature is 45°C to form the second copper layer on the surface of the second welding wire, obtaining the high-strength gas shielded welding wire #1.

[0041] In this embodiment, the first welding wire is obtained by performing surface degreasing and activation treatment on the wire rod. The silane coupling agent uses KH-550. In other embodiments, other silane coupling agents such as KH-560 can also be used.

[0042] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, and 0.08 part of a stabilizer, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methyl sulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, and 0.3 part of an additive, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0043] The high-strength gas shielded welding wire #1 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0044] Example 2: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0045] S1. Pretreatment: The wire rod is drawn to a diameter of 1.0 - 1.2 mm and a surface roughness of Ra ≤ 0.6 μm, then the wire rod is cleaned with a neutral enzyme cleaning agent at a temperature of 60°C and a pH of 7.5 for 15 min to remove surface grease, and then acidified with a mixed solution of citric acid and hydrogen peroxide with a mass ratio of 2 - 3:1 under ultrasonic assistance, and finally catalyzed with Pd-Sn colloid to obtain the first welding wire;

[0046] S2. Preparing the first copper layer by electroless copper plating: The first welding wire is put into the first copper plating solution and chemically electroplated for 5 min at a temperature of 55°C and a rotation speed of 5 m / min to form the first copper layer on the surface of the first welding wire. After the first copper layer is immersed in a 1% silane coupling agent for 5 min, it is dried at a temperature of 60°C to obtain the second welding wire;

[0047] S3. Preparing the second copper layer by electroplating copper: The second welding wire is electroplated with copper using the second copper plating solution at a current density of 15 A / dm 2 , and the electroplating temperature is 45°C to form the second copper layer on the surface of the second welding wire, and the high-strength gas shielded welding wire #2 is obtained.

[0048] In this example, the wire rod uses a low-alloy steel wire rod. In other examples, the wire rod can also use a low-carbon steel wire rod. The rest is the same as in Example 1.

[0049] The high-strength gas shielded welding wire #2 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0050] Example 3: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0051] S1. Preparation of the first copper layer by electroless copper plating: Place the first welding wire in the first copper plating solution and conduct electroless plating for 5 minutes under the conditions of a temperature of 55°C and a rotation speed of 5 m / min to form the first copper layer on the surface of the first welding wire. Immerse the first copper layer in a 1% silane coupling agent for 5 minutes and then dry it at 60°C to obtain the second welding wire;

[0052] S2. Preparation of the second copper layer by electroplating copper: Use the second copper plating solution to electroplate copper on the second welding wire at a current density of 15 A / dm 2 and an electroplating temperature of 45°C to form the second copper layer on the surface of the second welding wire and obtain the third welding wire;

[0053] S3. Sealing and post-treatment: Place the third welding wire in the sealing solution and soak it at 80°C for 3 minutes to form a film quickly, and then obtain the high-strength gas shielded welding wire #3 after passivation and drying.

[0054] In this embodiment, the first welding wire is obtained by degreasing and activating the surface of the wire rod. The sealing solution includes an acrylic emulsion and aziridine with a mass ratio of 15:1. The rest is the same as in Example 1.

[0055] The high-strength gas shielded welding wire #3 includes a wire rod and a copper plating layer. The copper plating layer includes a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0056] Example 4: A preparation process for a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0057] S1. Pretreatment: Draw the wire rod to a diameter of 1.0 - 1.2 mm and a surface roughness of Ra ≤ 0.6 μm. Then use a neutral enzyme cleaning agent to clean the wire rod for 15 minutes at a temperature of 60°C and a pH of 7.5 to remove surface grease. Then acidify the wire rod using a mixed solution of citric acid and hydrogen peroxide with a mass ratio of 2 - 3:1 under ultrasonic assistance. Finally, use Pd - Sn colloid for catalysis to obtain the first welding wire;

[0058] S2. Preparation of the first copper layer by electroless copper plating: Place the first welding wire in the first copper plating solution and conduct electroless plating for 5 minutes under the conditions of a temperature of 55°C and a rotation speed of 5 m / min to form the first copper layer on the surface of the first welding wire. Immerse the first copper layer in a 1% silane coupling agent for 5 minutes and then dry it at 60°C to obtain the second welding wire;

[0059] S3. Preparation of the second copper layer by electroplating copper: Use the second copper plating solution to electroplate copper on the second welding wire at a current density of 15 A / dm 2 and an electroplating temperature of 45°C to form the second copper layer on the surface of the second welding wire and obtain the third welding wire;

[0060] S4. Sealing and post-treatment: Put the third welding wire into the sealing solution and soak it at 80 °C for 3 min to form a film quickly, and then obtain the high-strength gas-shielded welding wire #4 after passivation and drying.

[0061] By mass, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1; the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0062] The high-strength gas-shielded welding wire #4 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0063] Example 5: A preparation process of a high-strength gas-shielded welding wire and the high-strength gas-shielded welding wire.

[0064] The preparation process is the same as that of Example 4.

[0065] By mass, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer, 30 parts of a first composite complexing agent, the first composite complexing agent comprises sodium citrate and sodium potassium tartrate with a mass ratio of 1.5:1, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1; the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0066] The high-strength gas-shielded welding wire #5 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0067] Example 6: A preparation process of a high-strength gas-shielded welding wire and the high-strength gas-shielded welding wire.

[0068] The preparation process is the same as that of Example 4.

[0069] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer, 30 parts of a first composite complexing agent, and 0.15 part of carboxylated carbon nanotubes. The stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1. The first composite complexing agent comprises sodium citrate and sodium potassium tartrate with a mass ratio of 1.5:1. The second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive. The additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1. The sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1. The mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0070] The high-strength gas shielded welding wire #6 comprises a wire rod and a copper plating layer. The copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0071] Example 7: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0072] The preparation process is the same as that of Example 4.

[0073] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer. The stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1. The second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive, and 20 parts of a second composite complexing agent. The second composite complexing agent comprises sodium gluconate and amino sulfonic acid with a mass ratio of 1.3:1. The additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1. The sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1. The mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0074] The high-strength gas shielded welding wire #7 comprises a wire rod and a copper plating layer. The copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0075] Example 8: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0076] The preparation process is the same as that of Example 4.

[0077] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive, 20 parts of a second composite complexing agent, 0.1 part of nitrogen-doped carbon quantum dots, the second composite complexing agent comprises sodium gluconate and sulfamic acid with a mass ratio of 1.3:1, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises an acrylic emulsion and aziridine with a mass ratio of 15:1; and the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0078] The high-strength gas shielded welding wire #8 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0079] Example 9: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0080] The preparation process is the same as that of Example 4.

[0081] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of a stabilizer, 30 parts of a first composite complexing agent, the first composite complexing agent comprises sodium citrate and sodium potassium tartrate with a mass ratio of 1.5:1, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of an additive, 20 parts of a second composite complexing agent, the second composite complexing agent comprises sodium gluconate and sulfamic acid with a mass ratio of 1.3:1, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises an acrylic emulsion and aziridine with a mass ratio of 15:1; and the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0082] The high-strength gas shielded welding wire #9 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0083] Example 10: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0084] The preparation process is the same as that of Example 4.

[0085] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of stabilizer, 30 parts of first composite complexing agent, the first composite complexing agent comprises sodium citrate and potassium sodium tartrate with a mass ratio of 1.5:1, and the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of additive, 20 parts of second composite complexing agent, 0.1 part of nitrogen-doped carbon quantum dots, the second composite complexing agent comprises sodium gluconate and sulfamic acid with a mass ratio of 1.3:1, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1; the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0086] The high-strength gas shielded welding wire #10 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0087] Example 11: A preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0088] The preparation process is the same as that of Example 4.

[0089] By mass parts, the first copper plating solution comprises 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of stabilizer, 30 parts of first composite complexing agent, 0.15 part of carboxylated carbon nanotubes, the stabilizer comprises 2,2'-bipyridine and thiourea with a mass ratio of 2:1, and the first composite complexing agent comprises sodium citrate and potassium sodium tartrate with a mass ratio of 1.5:1; the second copper plating solution comprises 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, 0.3 part of additive, 20 parts of second composite complexing agent, the second composite complexing agent comprises sodium gluconate and sulfamic acid with a mass ratio of 1.3:1, and the additive comprises polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1; the sealing solution comprises acrylic emulsion and aziridine with a mass ratio of 15:1; the mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0090] The high-strength gas shielded welding wire #11 comprises a wire rod and a copper plating layer, and the copper plating layer comprises a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0091] Example 12: Preparation process of a high-strength gas shielded welding wire and the high-strength gas shielded welding wire.

[0092] The preparation process is the same as that in Example 4.

[0093] By mass, the first copper plating solution includes 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, 0.08 part of stabilizer, 30 parts of the first composite complexing agent, and 0.15 part of carboxylated carbon nanotubes. The stabilizer includes 2,2'-bipyridine and thiourea with a mass ratio of 2:1. The first composite complexing agent includes sodium citrate and sodium potassium tartrate with a mass ratio of 1.5:1. The second copper plating solution includes 40 parts of copper sulfate, 80 parts of sodium methyl sulfonate, 20 parts of boric acid-triethanolamine buffer solution, 0.3 part of potassium perfluorooctane sulfonate, 0.3 part of additive, 20 parts of the second composite complexing agent, and 0.1 part of nitrogen-doped carbon quantum dots. The second composite complexing agent includes sodium gluconate and sulfamic acid with a mass ratio of 1.3:1. The additive includes polyaspartic acid and sulfobetaine with a mass ratio of 1.5:1. The sealing solution includes acrylic emulsion and aziridine with a mass ratio of 15:1. The mass ratio of the first copper plating solution to the second copper plating solution is 1:2.

[0094] The high-strength gas shielded welding wire #12 includes a wire rod and a copper plating layer. The copper plating layer includes a first copper layer with a thickness of 1.5 μm and a second copper layer with a thickness of 10 μm.

[0095] Comparative Example 1: This comparative example provides a preparation process of a comparative high-strength gas shielded welding wire and the comparative high-strength gas shielded welding wire D1, which is the same as that in Example 4, except that in step S2, for the preparation of the first copper layer by electroless copper plating: the first welding wire is placed in the first copper plating solution and chemically electroplated for 3 - 5 minutes at a temperature of 54 - 56 °C and a rotation speed of 3 - 5 m / min to form the first copper layer on the surface of the first welding wire, and the second welding wire is obtained.

[0096] Comparative Example 2: This comparative example provides a preparation process of a comparative high-strength gas shielded welding wire and the comparative high-strength gas shielded welding wire D2, which is the same as that in Example 4, except that in step S4, post-treatment: the third welding wire is passivated and dried to obtain the high-strength gas shielded welding wire D2.

[0097] Comparative Example 3: This comparative example provides a preparation process of a comparative high-strength gas shielded welding wire and the comparative high-strength gas shielded welding wire D3. The preparation process includes the following steps:

[0098] S1. Pretreatment: The wire rod is drawn to a diameter of 1.0 - 1.2 mm with a surface roughness of Ra ≤ 0.6 μm. Then, the wire rod is cleaned with a neutral enzyme cleaning agent at a temperature of 60°C and a pH of 7.5 for 15 minutes to remove surface grease. Next, the wire rod is acidified with a mixed solution of citric acid and hydrogen peroxide in a mass ratio of 2 - 3:1 under ultrasonic assistance. Finally, Pd - Sn colloid catalysis is used to obtain the first welding wire;

[0099] S2. Preparation of copper layer by electroless copper plating: The first welding wire is placed in the copper plating solution and chemically electroplated for 5 minutes at a temperature of 55°C and a rotation speed of 5 m / min to form a copper layer on the surface of the first welding wire, obtaining the second welding wire;

[0100] S3. Sealing and post - treatment: The second welding wire is placed in the sealing solution and soaked at 80°C for 3 minutes to form a film rapidly. Then, it is passivated and dried to obtain the high - strength gas shielded welding wire D3.

[0101] The copper plating solution includes 15 parts of copper sulfate, 30 parts of sodium hypophosphite, 15 parts of sodium hydroxide, 0.03 part of sodium dodecylbenzenesulfonate, and 0.08 part of stabilizer. The stabilizer includes 2,2'-bipyridine and thiourea in a mass ratio of 2:1, and the others are the same as in Example 4.

[0102] Comparative Example 4: This comparative example provides a preparation process for comparing a high - strength gas shielded welding wire and the comparative high - strength gas shielded welding wire D4. The preparation process includes the following steps:

[0103] S1. Pretreatment: The wire rod is drawn to a diameter of 1.0 - 1.2 mm with a surface roughness of Ra ≤ 0.6 μm. Then, the wire rod is cleaned with a neutral enzyme cleaning agent at a temperature of 60°C and a pH of 7.5 for 15 minutes to remove surface grease. Next, the wire rod is acidified with a mixed solution of citric acid and hydrogen peroxide in a mass ratio of 2 - 3:1 under ultrasonic assistance. Finally, Pd - Sn colloid catalysis is used to obtain the first welding wire;

[0104] S2. Preparation of copper layer by electroplating copper: The first welding wire is electroplated with copper using the copper plating solution at a current density of 15 A / dm 2 , and the electroplating temperature is 45°C to form a copper layer, obtaining the second welding wire;

[0105] S3. Sealing and post - treatment: The second welding wire is placed in the sealing solution and soaked at 80°C for 3 minutes to form a film rapidly. Then, it is passivated and dried to obtain the high - strength gas shielded welding wire D4.

[0106] The copper plating solution includes 40 parts of copper sulfate, 80 parts of sodium methylsulfonate, 20 parts of boric acid - triethanolamine buffer solution, 0.3 part of potassium perfluorooctanesulfonate, and 0.3 part of additive. The additive includes polyaspartic acid and sulfobetaine in a mass ratio of 1.5:1, and the others are the same as in Example 4.

[0107] Comparative Example 5: This comparative example provides a preparation process for comparing a high-strength gas shielded welding wire and a comparative high-strength gas shielded welding wire D5. The preparation process is the same as that of Example 4, except that: 0.03 parts of sodium dodecylbenzenesulfonate are missing in the first copper plating solution.

[0108] Comparative Example 6: This comparative example provides a preparation process for comparing a high-strength gas shielded welding wire and a comparative high-strength gas shielded welding wire D6. The preparation process is the same as that of Example 4, except that: 0.08 parts of stabilizer are missing in the first copper plating solution.

[0109] Comparative Example 7: This comparative example provides a preparation process for comparing a high-strength gas shielded welding wire and a comparative high-strength gas shielded welding wire D7. The preparation process is the same as that of Example 4, except that: 0.3 parts of potassium perfluorooctanesulfonate are missing in the second copper plating solution.

[0110] Comparative Example 8: This comparative example provides a preparation process for comparing a high-strength gas shielded welding wire and a comparative high-strength gas shielded welding wire D8. The preparation process is the same as that of Example 4, except that: sodium chloride is selected to replace sodium methylsulfonate in the second copper plating solution.

[0111] Comparative Example 9: This comparative example provides a preparation process for comparing a high-strength gas shielded welding wire and a comparative high-strength gas shielded welding wire D9. The preparation process is the same as that of Example 4, except that: a mixture of 2-thiazolinyl polydithiopropanesulfonate and N,N-dimethyldithiocarbamoylpropane sulfonate is selected to replace polyaspartic acid and sulfobetaine in the second copper plating solution.

[0112] Welding tests were carried out on the copper-free welding wires #1-#12 of Examples 1-12 and the comparative copper-free welding wires D1-D9 in Comparative Examples 1-9, as shown in Table 1. The welding performance is shown in Table 2, including salt spray test, arc stability test, welding spatter amount test, wire feeding performance test, copper layer adhesion test, and copper layer bonding force test. Among them, the salt spray test was carried out according to the ISO9277 standard for 96 hours of salt spray test to observe the corrosion situation of the copper plating layer surface; the copper layer adhesion test was carried out by the cross-cut method. The specific test steps were as follows: fix the welding wire to be tested, use a cross-cut knife with a tooth pitch of 1 mm to cut the plating layer at a 90° vertical angle to form a 10×10 grid (a total of 100 squares). The incision needs to penetrate the copper layer to the base wire rod. Stick the tape tightly to the grid area, press the tape with an eraser to eliminate air bubbles and enhance adhesion. After standing for 3-5 minutes, quickly peel off the tape at a 90° angle, avoiding tilting or shaking. Use a magnifying glass or microscope to observe the grid area and count the copper layer peeling area (%); the copper layer bonding force test was carried out by the tensile method ((ASTM B571)). The specific test steps were as follows: bond the test welding wire and the steel column with epoxy resin. After curing, vertically stretch it with a tensile machine until the plating layer peels off, and calculate the bonding force by substituting into the formula: Bonding force = maximum tensile force (N) / copper plating layer area (mm).

[0113] Table 1

[0114]

[0115] Table 2

[0116]

[0117] From the test data in Table 2, it can be seen that when comparing Example 1 with Examples 2-4, Example 2 added a pretreatment step, Example 3 added a sealing and post-treatment step, and Example 4 added a pretreatment, sealing and post-treatment step. The performance of the high-strength GMAW welding wires obtained in Examples 2-4 is better than that of Example 1. Especially in Example 4, the arc stability and wire feeding performance are excellent, the spatter rate is low, the tensile strength is high, the copper layer peeling area and the copper layer corrosion area are small, and the bonding force is large, and the overall performance is stable.

[0118] Compared with Example 4, in Example 5, the first copper plating solution in Example 5 is added with the first composite complexing agent, and in Example 7, the second copper plating solution in Example 7 is added with the second composite complexing agent, and the various properties of the obtained high-strength gas shielded welding wire are higher than the various properties of the high-strength gas shielded welding wire obtained in Example 4. Compared with Example 6, in Example 11, the second copper plating solution in Example 6 is added with the second composite complexing agent, and the various properties of the obtained high-strength gas shielded welding wire are better than those in Example 6. Compared with Example 5 and Example 7, in Example 9, the first copper plating solution in Example 5 is added with the first composite complexing agent, and the second copper plating solution in Example 7 is added with the second composite complexing agent, and the various properties of the obtained high-strength gas shielded welding wire are better than those in Example 5 and Example 7. That is because the sodium citrate in the first composite complex can react with Cu through carboxyl and hydroxyl groups. 2+ Forms a stable complex [Cu(C6H5O7)] 3- , prevent copper ions from hydrolyzing or precipitating, ensure the uniform release of copper ions in the plating solution, and improve the deep plating ability. At the same time, sodium citrate is environmentally friendly and non-toxic. Potassium sodium tartrate combines with copper ions in alkaline solution to form a soluble complex, which prevents copper ions from forming copper hydroxide precipitation and maintains the stability of the plating solution. The sodium gluconate in the second complex can react with Cu 2+ Formation of stable [Cu(C6H 11 O7)] 2- The complex prevents the copper ions from hydrolyzing or abnormally depositing in the second copper plating solution, maintains the uniformity of the second copper plating solution, and can also adjust the pH value of the second copper plating solution, maintain the acid-base environment of the electroplating reaction, improve the uniformity of the coating crystallization, maintain the corrosion inhibition performance under high temperature conditions, reduce the porosity of the coating, and improve the corrosion resistance. Aminosulfonic acid can promote the grain refinement of the second copper layer, form a dense and ductile copper coating, reduce the internal stress of the coating, adsorb on the metal surface in the second copper plating solution, inhibit the growth of dendrites, and improve the uniformity and bonding strength of the second copper layer.

[0119] Compared with Example 5, in Example 6, carboxylated carbon nanotubes are added to the first copper plating solution, and the performance of the obtained high-strength gas shielded welding wire is better than that of Example 5. The reason is that the carboxyl functional groups (-COOH) introduced on the surface of the carboxylated carbon nanotubes significantly enhance the hydrophilicity of the first copper plating solution, making it easier to disperse uniformly in the first copper plating solution and avoiding the problem of uneven coating caused by hydrophobic agglomeration. The carboxyl functional groups maintain the stable suspension state of the carbon nanotubes in the plating solution through electrostatic repulsion, ensuring their uniform distribution in the coating. The surface active sites of the carboxylated carbon nanotubes can form coordination bonds with copper ions, promoting the chemical combination of the copper coating and the carbon nanotubes and enhancing the overall mechanical properties of the coating. Coating the surface of the carbon nanotubes with a copper layer by electroless plating can improve the wettability between the carbon nanotubes and the metal matrix, reduce interface defects, and enhance the coating bonding strength. As a conductive enhancer, the carboxylated carbon nanotubes can construct a three-dimensional conductive network in the plating solution, accelerate the reduction process of copper ions, and improve the coating deposition rate and density. The carboxyl functional groups can adsorb copper ions as active sites, optimize the distribution of copper ions in the plating solution, inhibit the agglomeration of copper particles, and refine the coating grains.

[0120] Compared with Example 7, in Example 8, and compared with Example 9, in Example 10, nitrogen-doped carbon quantum dots are added to the second copper plating solution. The performance of the high-strength gas shielded welding wire obtained in Example 8 is better than that of Example 7, and the performance of the high-strength gas shielded welding wire obtained in Example 10 is better than that of Example 9. This is because the surface of the nitrogen-doped carbon quantum dots is rich in functional groups such as amino (-NH2) and carboxyl (-COOH), which can form stable coordination complexes with Cu 2+ ions, inhibit the hydrolysis or abnormal deposition of free copper ions, and maintain the uniformity of the second copper plating solution. The high specific surface area and hydrophilicity of the nitrogen-doped carbon quantum dots can adsorb copper particles, prevent agglomeration, and improve the dispersion stability of the plating solution, reducing the coating porosity. The nitrogen-doped property endows it with electrocatalytic activity, which can lower the activation energy of the copper ion reduction reaction, accelerate the electrochemical deposition rate, and improve the electroplating efficiency. Through the optimization of interfacial charge transfer, it promotes the uniform nucleation of copper crystal nuclei and forms a dense coating. The nitrogen-doped carbon quantum dots adsorbed on the electrode surface can serve as nucleation sites, inhibit the coarsening of copper grains, and improve the hardness and wear resistance of the coating. By surface adsorption, the internal stress in the coating is reduced, and the risk of cracks and warping is decreased.

[0121] Compared with Example 4, in Example 12, a first complexing agent and carboxylated carbon nanotubes are added to the first copper plating solution, and a second complexing agent and nitrogen-doped carbon quantum dots are added to the second copper plating solution. The performance of the obtained high-strength gas shielded welding wire is better than that of Example 4. In particular, the overall corrosion resistance, the adhesion and uniformity of the copper layer of the high-strength gas shielded welding wire #12 are much better than those of the high-strength gas shielded welding wire #4.

[0122] Comparing Comparative Example 1 with Example 4, the first copper layer was not immersed in the silane coupling agent with a concentration of 1%. The performance of the obtained comparative high-strength gas-shielded welding wire was inferior to that of the high-strength gas-shielded welding wire in Example 4. This is because when the first copper layer was immersed in the silane coupling agent, the silicon-oxygen group (Si-O-) in the silane coupling agent hydrolyzed with the metallic copper on the surface of the first copper layer to form chemical bonds, and the other end, the organic functional group (such as epoxy group, amino group), combined with the second copper plating solution, realizing the "molecular bridge" connection at the inorganic-organic interface, enhancing the chemical bonding strength between the second copper layer and the first copper layer, reducing the peeling risk caused by physical stress or environmental corrosion. At the same time, treating with the silane coupling agent can reduce the surface energy of the first copper layer, making it easier to wet with the second copper plating solution and reducing interface defects (such as bubbles, microcracks), thereby improving adhesion and uniformity.

[0123] Comparing Comparative Example 2 with Example 4, the third welding wire was not put into the sealing solution to form a film quickly. The performance of the comparative high-strength gas-shielded welding wire was inferior to that of the high-strength gas-shielded welding wire in Example 4. This is because the acrylic emulsion and aziridine in the sealing solution crosslink to form an acrylic resin polymer, and the polymer forms a film on the surface of the copper layer, which can seal the pores. The carboxyl groups contained in the resin can coordinate with metal ions, enhancing the adsorption force with the copper layer.

[0124] Comparing Comparative Example 3 with Example 4, only electroless copper plating was used for copper plating. Comparing Comparative Example 4 with Example 4, only electroplating copper plating was used for copper plating. The performance of the comparative high-strength gas-shielded welding wire was far inferior to that of the high-strength gas-shielded welding wire in Example 4. This is because electroless copper plating can achieve complete coverage on the surface of the wire rod with many surface grooves and microcracks after drawing through autocatalytic reaction. The electroless copper plating layer as the bottom layer can ensure the uniform growth of the subsequent electroplated copper layer, avoiding missing plating caused by uneven current distribution during electroplating and forming a uniform copper layer. And electroplating copper realizes rapid thickening on the basis of the electroless copper plating thin layer. The electroplated copper layer further strengthens the surface hardness and wear resistance on the basis of the electroless copper plating layer, prolongs the service life of the workpiece in the friction environment, improves the arc stability and wire feeding stability of the gas-shielded welding wire, and at the same time avoids a large amount of spatter.

[0125] Comparative Examples 5-9 are compared with Example 4. In the first copper plating solution of Comparative Example 3, sodium dodecylbenzenesulfonate is missing; in the first copper plating solution of Comparative Example 4, the stabilizer is missing; in the second copper plating solution of Comparative Example 5, potassium perfluorooctanesulfonate is missing; in the second copper plating solution of Comparative Example 6, sodium chloride replaces sodium methylsulfonate; in the second copper plating solution of Comparative Example 7, a mixture of sodium 2-thiazolinyl polydithiopropanesulfonate and sodium N,N-dimethyldithiocarbamoylpropane sulfonate replaces polyaspartic acid and sulfobetaine. The performance of the high-strength gas shielded welding wire in each comparison is inferior to that of the high-strength gas shielded welding wire in Example 4. From this, it can be seen that the materials after being missing or replaced cannot play a role in the high-strength gas shielded welding wire, but will instead reduce the role of the high-strength gas shielded welding wire. Therefore, each component cannot be randomly replaced by other materials.

[0126] The above are all preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A preparation process of a high-strength gas shielded welding wire, characterized in that, The preparation process of the high-strength gas shielded welding wire includes the following steps: Preparing the first copper layer by electroless copper plating: putting the first welding wire into the first copper plating solution, carrying out electroless plating for 3 - 5 minutes under the conditions of a temperature of 54 - 56 °C and a rotation speed of 3 - 5 m / min to form the first copper layer on the surface of the first welding wire, dipping the first copper layer into a 1% silane coupling agent for 3 - 5 minutes, and then drying it at a temperature of 55 - 60 °C to obtain the second welding wire; Preparation of the second copper layer by electroplating copper: Using a second copper plating solution to electroplate the second welding wire at a current density of 13 - 15 A / dm 2 , and electroplating copper at an electroplating temperature of 40 - 45 °C to form a second copper layer on the surface of the second welding wire, thereby obtaining the high-strength gas shielded welding wire; By mass, the first copper plating solution includes 15 - 20 parts of copper sulfate, 30 - 40 parts of sodium hypophosphite, 15 - 18 parts of sodium hydroxide, 0.01 - 0.05 parts of sodium dodecylbenzenesulfonate, 0.05 - 0.1 part of stabilizer, 30 - 40 parts of the first composite complexing agent, 0.1 - 0.2 part of carboxylated carbon nanotubes. The carboxylated carbon nanotubes are obtained by oxidizing carbon nanotubes in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:

1. The first composite complexing agent includes sodium citrate and potassium sodium tartrate with a mass ratio of 1 - 1.5:1, and the stabilizer includes 2,2'-bipyridine and thiourea with a mass ratio of 2 - 3:1; The second copper plating solution includes 30 - 50 parts of copper sulfate, 60 - 100 parts of sodium methyl sulfonate, 15 - 25 parts of boric acid - triethanolamine buffer solution, 0.1 - 0.5 part of potassium perfluorooctane sulfonate, 0.5 - 1 part of additive, 15 - 25 parts of the second composite complexing agent, 0.1 - 0.2 part of nitrogen-doped carbon quantum dots. The nitrogen-doped carbon quantum dots are prepared by a hydrothermal reaction using citric acid as the carbon source and ethylenediamine as the nitrogen source. The second composite complexing agent includes sodium gluconate and amino sulfonic acid with a mass ratio of 1.2 - 1.5:1, and the additive includes polyaspartic acid and thiobetaine with a mass ratio of 1 - 1.5:1; The mass ratio of the first copper plating solution to the second copper plating solution is 1:1.5 - 2.

2. The preparation process of a high-strength gas shielded welding wire according to claim 1, characterized in that, The preparation method of the first welding wire is as follows: drawing the wire rod to a diameter of 1.0 - 1.2 mm with a surface roughness of Ra ≤ 0.6 μm, then using a neutral enzyme cleaning agent to clean the wire rod for 10 - 15 minutes at a temperature of 55 - 60 °C and a pH of 7.0 - 7.5 to remove the surface grease, then acidifying the wire rod using a mixed solution of citric acid and hydrogen peroxide with a mass ratio of 2 - 3:1 under ultrasonic assistance, and finally using Pd - Sn colloid catalysis to obtain the first welding wire.

3. The preparation process of a high-strength gas shielded welding wire according to claim 1 or 2, characterized in that, The preparation process of the high-strength gas shielded welding wire also includes a sealing and post-treatment step. The sealing and post-treatment step is: putting the high-strength gas shielded welding wire into the sealing solution and soaking it at a temperature of 75 - 80 °C for 2 - 3 minutes to form a film quickly, and then passivating and drying it; the sealing solution includes acrylic emulsion and aziridine with a mass ratio of 10 - 20:

1.

4. A high-strength gas shielded welding wire prepared by the preparation process of the high-strength gas shielded welding wire described in any one of claims 1-3, characterized in that, The high-strength gas shielded welding wire includes a wire rod and a copper plating layer, and the copper plating layer includes a first copper layer and a second copper layer.

5. The high-strength gas shielded welding wire according to claim 4, characterized in that, The thickness of the first copper layer is 1 - 3 μm, and the thickness of the second copper layer is 5 - 15 μm.

6. The application of a high-strength gas shielded welding wire in the aerospace industry, the automotive manufacturing industry, the food machinery and medical device manufacturing industries, and in robotic welding scenarios, characterized in that, The high-strength gas shielded welding wire prepared by the preparation method of the high-strength gas shielded welding wire described in any one of claims 1-3, or the high-strength gas shielded welding wire described in any one of claims 4-5.

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