Al-Mg series welding wire and preparation method and application thereof

Abstract

The invention provides an Al-Mg series welding wire and a preparation method and application thereof. The method comprises the steps that alloy raw materials are smelted and cast according to the component proportion, an obtained aluminum alloy cast rod is sequentially subjected to homogenization treatment, extrusion, hot rough rolling, hot finish rolling, drawing and coiling, and the Al-Mg series welding wire is obtained; wherein hot finish rolling emulsion is further used for hot rough rolling and hot finish rolling, the mass concentration of the hot rough rolling emulsion is larger than that of the hot finish rolling emulsion, and the pH of the hot rough rolling emulsion is smaller than that of the hot finish rolling emulsion. Alloy elements are uniformly distributed by controlling alloy components and using homogenization treatment and an extrusion process, so that component segregation is effectively eliminated, the welding wire has relatively high strength, and the wire processing performance is improved; meanwhile, a reasonable wire processing technology is adopted, the components of rolling emulsion are regulated and controlled, the surface quality of the welding wire is improved, the prepared finished welding wire can guarantee stable combustion of electric arcs and a molten pool in the welding process, and the welding seam quality is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, and more specifically, to an Al-Mg welding wire, its preparation method, and its application. Background Technology

[0002] Al-Mg series welding wire is the most commonly used series of aluminum alloy welding wires, characterized by high strength and high toughness. Its applications include aerospace, marine vessels, and rail transportation. However, domestically produced welding wires still differ from imported ones, exhibiting issues such as poor surface quality and difficulty in guaranteeing batch-to-batch stability. Welding wires are typically produced using a continuous casting and rolling process, which is characterized by low cost and high efficiency. However, due to the nature of the equipment used, surface quality is difficult to guarantee.

[0003] Currently, there are shortcomings in the domestic production of high-end aluminum alloy welding wire, making it difficult to achieve domestic substitution for imported welding wire. Especially in fields such as aerospace, marine vessels, and rail transportation, welding wire not only needs excellent mechanical properties, but its surface quality must also meet stringent standards to ensure stability during the welding process and the quality of the weld. However, current Al-Mg based welding wires struggle to simultaneously achieve high strength and good surface properties, hindering further improvements in weld quality. Summary of the Invention

[0004] The main objective of this invention is to provide an Al-Mg welding wire, its preparation method, and its application, so as to solve the problem that Al-Mg welding wires in the prior art are difficult to achieve simultaneously with high strength, high surface quality, and low weld defects.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing an Al-Mg welding wire is provided. The Al-Mg welding wire, by weight percentage, comprises: Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, with the balance being Al and unavoidable impurity elements, with single impurity ≤0.05% and total impurities ≤0.15%. The preparation method includes the following steps: Step S1, melting and casting the alloy raw materials according to the component ratio to obtain an aluminum alloy casting rod; Step S2, homogenizing the aluminum alloy casting rod. The process involves processing to obtain an aluminum alloy billet; step S3, extruding the aluminum alloy billet to obtain an aluminum alloy extruded bar; step S4, hot rough rolling the aluminum alloy extruded bar using a hot rough rolling emulsion to obtain a hot rough rolled wire; step S5, hot finish rolling the hot rough rolled wire using a hot finish rolling emulsion to obtain a hot finish rolled wire; step S6, drawing the hot finish rolled wire to obtain a drawn wire; and step S7, coiling the drawn wire to obtain an Al-Mg welding wire. The mass concentration of the hot rough rolling emulsion is greater than that of the hot finish rolling emulsion, and the pH of the hot rough rolling emulsion is less than that of the hot finish rolling emulsion.

[0006] Furthermore, the mass concentration of the hot roughing emulsion is 7-10%, and the pH value is 6-7; and / or the mass concentration of the hot finishing emulsion is 6-6.9%, and the pH value is 7.1-8.

[0007] Furthermore, independently, by weight, the hot roughing emulsion and the hot finishing emulsion comprise 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of benzyl dimethyl tetradecylamine dihydrate, 3-6 parts of ethoxylated aliphatic alkylamines, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide, and 0.1-0.5 parts of phenolic antioxidants.

[0008] Furthermore, the initial rolling temperature for hot roughing is 500~530℃; and / or the initial rolling temperature for hot finishing is 400~440℃.

[0009] Furthermore, in step S6, drawing oil is also used during the drawing process, and the viscosity of the drawing oil is 90~110 mm. 2 / s, density is 0.8~1.0g / cm³ 3 .

[0010] Furthermore, by weight, the drawing oil comprises 20-30 parts mineral oil, 40-50 parts polyisobutylene, 15-25 parts fatty acid ester, 10-15 parts pentaerythritol ester, and 1-3 parts aniline antioxidant.

[0011] Furthermore, the casting temperature is 720~760℃; and / or the homogenization temperature is 450~500℃, and the holding time is 10~24h.

[0012] According to another aspect of the present invention, an Al-Mg based welding wire is provided, which is obtained using the preparation method described above.

[0013] Furthermore, the strength of Al-Mg welding wire is 450~500MPa, and the strength of deposited metal is 300~340MPa.

[0014] According to another aspect of the present invention, a welded joint is provided, which is obtained by welding the Al-Mg series welding wire of the present invention described above with a 5XXX series plate, and the weld grade is I.

[0015] By applying the technical solution of this invention, the alloy composition is controlled, and the alloy elements are evenly distributed using homogenization treatment and extrusion processes, effectively eliminating component segregation and resulting in welding wire with high strength and improved wire processing performance. At the same time, a reasonable wire processing technology is adopted, and the composition of the rolling emulsion is controlled to improve the surface quality of the welding wire, making its surface smooth, flat, and free of scratches. The finished welding wire prepared can ensure stable combustion of the electric arc and molten pool during the welding process, thereby reducing defects such as weld porosity and effectively improving weld quality. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A surface quality diagram of an Al-Mg welding wire according to Embodiment 1 of the present invention is shown;

[0018] Figure 2 A photograph of a welded joint according to Embodiment 1 of the present invention is shown;

[0019] Figure 3 The stress-strain curve of the welded joint according to Embodiment 1 of the present invention is shown. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] Terminology Explanation:

[0022] Deposited metal: It is the weld metal formed entirely by the melting of filler metal, and is the part of the weld that has melted the welding rod or wire.

[0023] As described in the background section of this invention, existing Al-Mg welding wires suffer from the problem of simultaneously achieving high strength, high surface quality, and low weld defects. To address this issue, in a typical embodiment of this invention, a method for preparing an Al-Mg welding wire is provided. The Al-Mg welding wire, by weight percentage, comprises: Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, with the balance being Al and unavoidable impurity elements, with single impurity ≤0.05% and total impurities ≤0.15%. The preparation method includes the following steps: Step S1, melting and casting the alloy raw materials according to the component ratio to obtain an aluminum alloy casting rod; Step S2, homogenizing the aluminum alloy casting rod... The process involves several steps: 1) Homogenization treatment to obtain an aluminum alloy billet; 2) Extruding the aluminum alloy billet to obtain an aluminum alloy extruded bar; 3) Hot rough rolling of the aluminum alloy extruded bar using a hot rough rolling emulsion to obtain a hot rough rolled wire; 4) Hot finishing rolling of the hot rough rolled wire using a hot finishing rolling emulsion to obtain a hot finishing rolled wire; 5) Drawing of the hot finishing rolled wire to obtain a drawn wire; 6) Coiling of the drawn wire to obtain an Al-Mg welding wire. The mass concentration of the hot rough rolling emulsion is greater than that of the hot finishing rolling emulsion, and the pH of the hot rough rolling emulsion is less than that of the hot finishing rolling emulsion.

[0024] Specifically, this invention first melts and casts the alloy raw materials according to the component ratio to obtain aluminum alloy cast rods. The contents of Si, Fe, Cu, and Mn are strictly controlled at low levels, primarily to reduce defects during the welding process. For example, excessive Si and Fe content can lead to the formation of brittle intermetallic compounds, affecting the weld toughness; low Cu content helps reduce hot cracking; and a small amount of Mn can improve weld toughness and also helps refine weld grains.

[0025] The Mg content mentioned above is a major strengthening element that can significantly improve the strength and hardness of the welding wire while maintaining good corrosion resistance. Its content is between 5.6% and 6.6% to achieve the best balance between strength and welding performance. Too high or too low Mg content will affect the plasticity of the welding wire and the fluidity of the molten metal during welding, thus affecting the quality of the weld. The preferred content is 6.2% to 6.5%.

[0026] An appropriate amount of Ti can refine the grains of the welding wire and weld, improving their toughness. Unavoidable impurities such as Cr and Zn, when controlled within reasonable ranges, help maintain the purity of the welding wire, reduce the impact of impurities on its performance, and improve its strength and surface quality.

[0027] The alloy raw material can be a pure alloy ingot or an intermediate alloy. The casting process can use electromagnetic stirring to make the elements evenly distributed, adopt two-stage online degassing, and then introduce it into the crystallizer for casting to reduce oxides and inclusions, thereby improving the internal structure and surface quality of the welding wire.

[0028] After obtaining the aluminum alloy cast rod, it undergoes homogenization and extrusion treatments to ensure uniform distribution of alloying elements, effectively eliminate component segregation, and improve the strength and plasticity of the welding wire, preventing wire breakage and achieving the goals of grain refinement, increased strength, and improved surface quality, resulting in an extruded aluminum alloy rod. The extruded aluminum alloy rod is then subjected to hot rough rolling and hot finish rolling. During rough rolling, an emulsion with differentiated concentrations and pH is used to reduce friction and improve surface quality, resulting in a hot-finished wire. Finally, the hot-finished wire is drawn to further refine the grains, improve the surface smoothness of the welding wire, reduce surface defects, and enhance wire feeding stability, resulting in a drawn wire that is then coiled to obtain the Al-Mg welding wire. Both the hot rough rolling emulsion and the hot finish rolling emulsion are water-based emulsions.

[0029] It should be noted that the present invention limits the mass concentration of the hot roughing emulsion to be greater than that of the hot finishing emulsion, and the pH of the hot roughing emulsion to be less than that of the hot finishing emulsion. The purpose is to improve the surface quality of the wire by combining the wire drawing operation, reduce defects such as pits and scratches, and lay the foundation for subsequent processing into bright welding wire.

[0030] Specifically, during hot roughing, a high concentration of emulsion provides better lubrication, reduces friction between the rolls and the wire, and prevents surface damage such as scratches. Emulsions with lower pH values ​​exhibit better oil-water separation, separating out more oil components, resulting in superior lubrication.

[0031] During hot finishing rolling, the emulsion concentration is relatively low, primarily to facilitate the biting of small-diameter wire rods into the rolls and prevent slippage. It also reduces emulsion residue, as excessive residue can cause surface defects during subsequent drawing and heat treatment. The low-concentration emulsion is also easier to clean, improving the cleanliness of the wire surface and resulting in high-quality welding wire. Using an emulsion with a higher pH value during hot finishing rolling makes the preparation process more stable, ensuring a higher yield during continuous rolling, and also contributing to a higher surface finish on the wire.

[0032] The differentiated hot-rolled emulsion solution of this invention can ensure the processing performance of the material while taking into account the surface quality of the welding wire, which helps to enable Al-Mg welding wire to achieve both high strength and high surface quality.

[0033] In summary, this invention achieves high strength in welding wire by controlling alloy composition and employing homogenization and extrusion processes. Simultaneously, it utilizes a reasonable wire processing technology and adjusts the composition of the rolling emulsion to improve the surface quality of the welding wire, resulting in a smooth surface free from scratches and other quality issues. The prepared welding wire ensures stable arc and molten pool combustion during welding, thereby reducing defects such as weld porosity. The welding wire obtained using this method exhibits good continuous wire feeding stability, and both the strength of the deposited metal and the quality of the weld joint are significantly improved.

[0034] In a preferred embodiment, the mass concentration of the hot roughing emulsion is 7-10%, and the pH value is 6-7; and / or the mass concentration of the hot finishing emulsion is 6-6.9%, and the pH value is 7.1-8. The pH value can be controlled by adding external acids or alkalis (such as organic acids or organic amines; the organic acids can be one or more of acetic acid, oxalic acid, malic acid, citric acid, or other types of organic acids; the organic amines can be one or more of ethylenediamine, triethanolamine, aniline, or other types of organic amines). Using the above-mentioned high-concentration, low-pH emulsion in the hot roughing stage provides better lubrication and surface cleaning effects, helping to maintain the high strength and plasticity of the wire. Using the above-mentioned low-concentration, high-pH emulsion in the hot finishing stage can further improve the surface quality of the wire, resulting in a smooth and defect-free surface of the finished welding wire.

[0035] For similar reasons, in a preferred embodiment, the hot roughing emulsion and the hot finishing emulsion, independently by weight, comprise 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of benzyl dimethyl tetradecylamine dihydrate, 3-6 parts of ethoxylated aliphatic alkylamines, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide, and 0.1-0.5 parts of phenolic antioxidants. In mineral oil solvent environments, aliphatic hydrocarbons provide excellent lubrication and cooling properties while protecting metal surfaces and reducing oxidation and corrosion. Benzyl dimethyltetradecylamine dihydrate and N,N-dimethyldodecylamine N-oxide, as surfactants, reduce surface tension at the oil-water interface, forming a stable and dispersed emulsion that provides good lubrication, reduces friction during rolling, and helps maintain the high strength and surface integrity of the welding wire material. Ethoxylated aliphatic alkylamines help maintain the stability of the emulsion, reduce foaming, and ensure its cooling and lubrication effects. Phenolic antioxidants prevent the base oil and additives in the emulsion from oxidizing at high temperatures, maintaining the stability of the emulsion's performance.

[0036] Through the rational formulation and use of the above components, the hot roughing and finishing emulsions not only provide excellent cooling, lubrication, and corrosion protection, reducing surface defects such as scratches and oxidation during processing, but also ensure the strength and plasticity of the welding wire material at high temperatures, thereby achieving the goal of producing high-strength and high-surface-quality Al-Mg welding wires. In the hot roughing stage, controlling the emulsion to a high concentration and low pH value allows for efficient processing of large-diameter wires while protecting surface quality. In the hot finishing stage, controlling the emulsion to a low concentration and high pH value allows for more precise control of the wire surface treatment, ensuring that the final finished welding wire achieves optimal surface finish and strength.

[0037] In order to better coordinate with specific emulsions and enable Al-Mg welding wires to exhibit high strength and high surface quality after processing, thereby meeting the requirements for welding wire use and obtaining welds with fewer defects, in a preferred embodiment, the wire diameter is reduced by continuous rolling, with the initial rolling temperature of hot roughing at 500~530℃ and / or the initial rolling temperature of hot finishing at 400~440℃.

[0038] Setting the initial rolling temperature in hot roughing rolling within a relatively high range helps to give the material higher plasticity in the early stages of hot working, reducing work hardening and making the material easier to deform, thereby further reducing cracks or fractures. A higher initial rolling temperature also helps to improve the material's flowability, facilitating subsequent rolling processes. Setting the initial rolling temperature in hot finishing rolling within the above range can further improve the material's plasticity, ensuring precise control of wire dimensions and shape during finishing rolling, while reducing surface defects.

[0039] The use of wire drawing oil during the drawing process protects the wire surface from damage, reduces heat generation during drawing, and ensures the mechanical properties of the material. In a preferred embodiment, in step S6, wire drawing oil is also used during drawing, and the viscosity of the wire drawing oil is 90~110 mm. 2 / s, density is 0.8~1.0g / cm³ 3 High-viscosity wire drawing oil can form a thicker oil film between the metal wire and the die, providing good lubrication and reducing friction and wear during the drawing process. This further reduces defects such as scratches on the surface of the welding wire. It also helps to carry away the heat generated during the drawing process, preventing the wire from overheating and thus reducing the degradation of material properties caused by high temperatures, thereby improving the strength of the welding wire. During the drawing process, good lubrication can also reduce the adhesion between the metal wire and the die, reduce wire breakage, improve the continuity of the production process and the integrity of the welding wire, and help maintain the high strength performance of the welding wire.

[0040] When the density of the wire drawing oil is within the above-mentioned range, it can be better distributed evenly on the surface of the metal wire, ensuring good lubrication of all contact surfaces and forming a stable and complete oil film. This is beneficial for improving the surface quality of the welding wire and reducing defects. Wire drawing oils with the above-mentioned viscosity and density can provide better lubrication and cooling during the drawing process, reducing friction and heat between the metal wire and the die, as well as damage to the welding wire surface. While maintaining its high strength, it also helps to achieve a high surface quality for the welding wire.

[0041] In a preferred embodiment, the drawing oil comprises, by weight, 20-30 parts mineral oil, 40-50 parts polyisobutylene, 15-25 parts fatty acid ester, 10-15 parts pentaerythritol ester, and 1-3 parts aniline antioxidant.

[0042] Among these components, mineral oil provides a stable lubrication base, ensuring continuity during processing; polyisobutylene enhances the oil's adhesion, ensuring a uniform coating of the drawing oil on the welding wire surface, further improving lubricity and preventing surface defects; pentaerythritol esters and fatty acid esters, as highly efficient lubricants, significantly reduce friction between the metal wire and the die, minimizing surface scratches and maintaining a smooth surface; aniline antioxidants effectively inhibit oil oxidation, extending the service life of the drawing oil and indirectly supporting the maintenance of high surface quality. This composition of the drawing oil significantly improves the strength and surface quality of Al-Mg welding wire while facilitating processing, meeting the stringent performance requirements of high-end applications.

[0043] To further promote the complete dissolution of alloying elements and the uniformity of microstructure, laying a high-strength foundation for subsequent processing, in a preferred embodiment, the casting temperature is 720~760℃; and / or the homogenization temperature is 450~500℃, with a holding time of 10~24h. Homogenization parameters within the above range are more conducive to eliminating casting stress, refining grains, further improving the overall performance of the material, and reducing surface defects. Preferably, the extrusion ratio is 7~10. This extrusion ratio also helps optimize the material's rheological properties, improve the density of the welding wire's internal structure, reduce defects such as porosity, and improve surface quality.

[0044] In another typical embodiment of the present invention, an Al-Mg based welding wire is also provided, obtained using the preparation method described above. Due to the use of the preparation method of the present invention, it can achieve both high strength and high surface quality, resulting in significantly improved welding performance.

[0045] It should be noted that due to the special nature of the alloy field and the limitations of existing testing and characterization methods, it is difficult to comprehensively and quantitatively characterize the complex microstructure of the Al-Mg welding wire obtained above. Therefore, this application has limited the Al-Mg welding wire prepared using the above method. By controlling the alloy composition and using homogenization treatment and extrusion processes to ensure uniform distribution of alloying elements, compositional segregation is effectively eliminated, resulting in higher strength and improved wire processing performance. Simultaneously, a reasonable wire processing technology and control of the rolling emulsion composition improve the surface quality of the welding wire, making it smooth, flat, and free of scratches. The resulting finished welding wire ensures stable arc and molten pool combustion during welding, thereby reducing defects such as weld porosity and effectively improving weld quality. Experiments show that the Al-Mg welding wire obtained in this application has higher comprehensive mechanical properties.

[0046] Specifically, in a preferred embodiment, the strength of the Al-Mg welding wire is 450~500MPa, and the strength of the deposited metal is 300~340MPa.

[0047] In another typical embodiment of the present invention, a welded joint is also provided, which is obtained by welding the Al-Mg series welding wire of the present invention to 5XXX series plates. The weld grade is Grade I, and the grade standard is determined by CB / T 3747-2013 "Quality Requirements for Welded Joints of Marine Aluminum Alloys". The weld defects are significantly reduced and the weld quality is significantly improved.

[0048] Typical, but not limiting, hot roughing emulsions have a mass concentration of 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or any two of these values, and a pH value of 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, or any two of these values.

[0049] Typical, but not limiting, hot finishing emulsions have a mass concentration of 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, or any two of these values, and a pH value of 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, or any two of these values.

[0050] Typical, but not limiting, drawing oil viscosity is 90 mm. 2 / s, 92 mm 2 / s, 95 mm 2 / s, 98 mm 2 / s, 100 mm 2 / s, 102 mm 2 / s, 105 mm 2 / s, 108 mm 2 / s, 110mm 2 / s or any two of its values, with a density of 0.8 g / cm³. 3 0.85 g / cm 3 0.9 g / cm 3 0.95 g / cm 3 1.0 g / cm 3 Or a range of values ​​consisting of any two of its values.

[0051] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0052] Example 1

[0053] A method for preparing Al-Mg based welding wire, the composition of which is shown in Table 1, includes the following steps:

[0054] Step S1: According to the composition ratio, high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloy, aluminum-iron master alloy and aluminum-titanium master alloy are smelted and cast. Electromagnetic stirring is used to make the element distribution uniform. Two-stage online degassing is used and introduced into the crystallizer for casting (casting temperature is 740℃) to obtain aluminum alloy rods with φ=420mm.

[0055] Step S2: Homogenize the aluminum alloy casting rod (temperature 470℃, holding time 18h) to obtain aluminum alloy billet.

[0056] Step S3: Extrude the aluminum alloy billet (extrusion ratio of 8.3) to obtain an aluminum alloy extrusion bar with φ=145mm.

[0057] Step S4: Hot rough rolling of aluminum alloy extrusion bar (rolling temperature is 510℃). Hot rough rolling also uses hot rough rolling emulsion to obtain hot rough rolled wire with φ=25mm.

[0058] Step S5: Hot finishing rolling is performed on the hot roughing wire (the initial rolling temperature is 420℃). Hot finishing rolling also uses hot finishing emulsion to obtain hot finishing wire with φ=9mm.

[0059] Step S6: The hot-rolled wire is drawn using drawing oil to obtain a drawn wire with a diameter of φ=3.5mm.

[0060] Step S7: The drawn wire is coiled to obtain a coiled Al-Mg welding wire with φ=1.2mm that can be automatically fed.

[0061] The hot roughing and finishing emulsions used include 60 parts mineral oil, 12 parts trimethylol oleate, 8 parts fatty hydrocarbons, 7 parts benzyl dimethyl tetradecylamine dihydrate, 5 parts ethoxylated fatty alkylamines, 4 parts sodium petroleum sulfonate, 2 parts N,N-dimethyldodecylamine N-oxide, and 0.3 parts phenolic antioxidants. The hot roughing emulsion has a mass concentration of 8.5% and a pH of 6.5; the hot finishing emulsion has a mass concentration of 6.5% and a pH of 7.5.

[0062] The drawing oil used comprises 25 parts mineral oil, 45 parts polyisobutylene, 20 parts fatty acid ester, 12 parts pentaerythritol ester, and 2 parts aniline antioxidant. The viscosity of the drawing oil is 100 mm. 2 / s, density is 0.9g / cm³ 3 .

[0063] Examples 2 to 5

[0064] The difference from Example 1 is that the composition of the Al-Mg welding wire is different, as detailed in Table 1.

[0065] Example 6

[0066] The difference from Example 1 is that the hot roughing emulsion used has a mass concentration of 7% and a pH value of 6; the hot finishing emulsion has a mass concentration of 6% and a pH value of 7.1. Both the hot roughing and hot finishing emulsions comprise 50 parts mineral oil, 10 parts trimethylol oleate, 10 parts aliphatic hydrocarbons, 5 parts benzyl dimethyl tetradecylamine dihydrate, 6 parts ethoxylated aliphatic alkylamines, 3 parts sodium petroleum sulfonate, 3 parts N,N-dimethyldodecylamine N-oxide, and 0.1 parts phenolic antioxidants.

[0067] Example 7

[0068] The difference from Example 1 is that the hot roughing emulsion used has a mass concentration of 10% and a pH value of 7; the hot finishing emulsion has a mass concentration of 6.9% and a pH value of 8. Both the hot roughing and hot finishing emulsions comprise 70 parts mineral oil, 15 parts trimethylol oleate, 5 parts aliphatic hydrocarbons, 8 parts benzyl dimethyl tetradecylamine dihydrate, 3 parts ethoxylated aliphatic alkylamines, 5 parts sodium petroleum sulfonate, 1 part N,N-dimethyldodecylamine N-oxide, and 0.5 parts phenolic antioxidants.

[0069] Example 8

[0070] The difference from Example 1 is that the viscosity of the drawing oil used is 90 mm. 2 / s, density is 0.8g / cm³ 3The drawing oil consists of 30 parts mineral oil, 50 parts polyisobutylene, 15 parts fatty acid ester, 15 parts pentaerythritol ester, and 1 part aniline antioxidant.

[0071] Example 9

[0072] The difference from Example 1 is that the viscosity of the drawing oil used is 110 mm. 2 / s, density is 1.0g / cm³ 3 The drawing oil consists of 20 parts mineral oil, 40 parts polyisobutylene, 25 parts fatty acid esters, 10 parts pentaerythritol esters, and 3 parts aniline antioxidant.

[0073] Example 10

[0074] A method for preparing Al-Mg based welding wire, wherein the composition of the Al-Mg based welding wire is the same as in Example 1, and the preparation method includes the following steps:

[0075] Step S1: According to the composition ratio, high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloy, aluminum-iron master alloy and aluminum-titanium master alloy are smelted and cast. Electromagnetic stirring is used to make the element distribution uniform. Two-stage online degassing is used and introduced into the crystallizer for casting (casting temperature is 720℃) to obtain aluminum alloy casting rods with φ=420mm.

[0076] Step S2: Homogenize the aluminum alloy casting rod (temperature 450℃, holding time 24h) to obtain aluminum alloy billet.

[0077] Step S3: Extrude the aluminum alloy billet (extrusion ratio of 7) to obtain an aluminum alloy extrusion bar;

[0078] Step S4: Hot rough rolling of aluminum alloy extrusion bar (rolling temperature is 500℃). Hot rough rolling also uses hot rough rolling emulsion to obtain hot rough rolled wire.

[0079] Step S5: The hot rough-rolled wire is hot-finished (the initial rolling temperature is 400°C). The hot finishing rolling also uses a hot finishing emulsion to obtain the hot-finished wire.

[0080] Step S6: The hot-rolled wire is drawn using drawing oil to obtain the drawn wire.

[0081] Step S7: The drawn wire is coiled to obtain a coiled Al-Mg welding wire that can be automatically fed.

[0082] The hot roughing and finishing emulsions used include 60 parts mineral oil, 12 parts trimethylol oleate, 8 parts fatty hydrocarbons, 7 parts benzyl dimethyl tetradecylamine dihydrate, 5 parts ethoxylated fatty alkylamines, 4 parts sodium petroleum sulfonate, 2 parts N,N-dimethyldodecylamine N-oxide, and 0.3 parts phenolic antioxidants. The hot roughing emulsion has a mass concentration of 8.5% and a pH of 6.5; the hot finishing emulsion has a mass concentration of 6.5% and a pH of 7.5.

[0083] The drawing oil used comprises 25 parts mineral oil, 45 parts polyisobutylene, 20 parts fatty acid ester, 12 parts pentaerythritol ester, and 2 parts aniline antioxidant. The viscosity of the drawing oil is 100 mm. 2 / s, density is 0.9g / cm³ 3 .

[0084] Example 11

[0085] A method for preparing Al-Mg based welding wire, wherein the composition of the Al-Mg based welding wire is the same as in Example 1, and the preparation method includes the following steps:

[0086] Step S1: According to the composition ratio, high-purity aluminum ingots, magnesium blocks, copper blocks, aluminum-manganese master alloy, aluminum-iron master alloy and aluminum-titanium master alloy are smelted and cast. Electromagnetic stirring is used to make the element distribution uniform. Two-stage online degassing is used and introduced into the crystallizer for casting (casting temperature is 760℃) to obtain aluminum alloy rods with φ=420mm.

[0087] Step S2: Homogenize the aluminum alloy casting rod (temperature 500℃, holding time 10h) to obtain aluminum alloy billet.

[0088] Step S3: Extrude the aluminum alloy billet (extrusion ratio of 10) to obtain an aluminum alloy extrusion bar;

[0089] Step S4: Hot rough rolling of aluminum alloy extrusion bar (rolling temperature is 530°C). Hot rough rolling also uses hot rough rolling emulsion to obtain hot rough rolled wire.

[0090] Step S5: The hot rough-rolled wire is hot-finished (the initial rolling temperature is 440°C). The hot finishing rolling also uses a hot finishing emulsion to obtain the hot-finished wire.

[0091] Step S6: The hot-rolled wire is drawn using drawing oil to obtain the drawn wire.

[0092] Step S7: The drawn wire is coiled to obtain a coiled Al-Mg welding wire that can be automatically fed.

[0093] The hot roughing and finishing emulsions used include 60 parts mineral oil, 12 parts trimethylol oleate, 8 parts fatty hydrocarbons, 7 parts benzyl dimethyl tetradecylamine dihydrate, 5 parts ethoxylated fatty alkylamines, 4 parts sodium petroleum sulfonate, 2 parts N,N-dimethyldodecylamine N-oxide, and 0.3 parts phenolic antioxidants. The hot roughing emulsion has a mass concentration of 8.5% and a pH of 6.5; the hot finishing emulsion has a mass concentration of 6.5% and a pH of 7.5.

[0094] The drawing oil used comprises 25 parts mineral oil, 45 parts polyisobutylene, 20 parts fatty acid ester, 12 parts pentaerythritol ester, and 2 parts aniline antioxidant. The viscosity of the drawing oil is 100 mm. 2 / s, density is 0.9g / cm³ 3 .

[0095] Comparative Example 1

[0096] The difference from Example 1 is that hot roughing emulsion is not used.

[0097] Comparative Example 2

[0098] The difference from Example 1 is that hot finishing emulsion is not used.

[0099] Comparative Example 3

[0100] The difference from Example 1 is that the hot roughing emulsion used has a mass concentration of 6% and a pH value of 8; the hot finishing emulsion has a mass concentration of 10% and a pH value of 6.

[0101] The Al-Mg welding wires prepared in the above examples and comparative examples were subjected to strength tests and deposited metal strength tests. The results are shown in Table 2.

[0102] The Al-Mg welding wires prepared in the above examples and comparative examples were welded to 5A06 plates to obtain welded joints. The weld grade was measured, and the results are shown in Table 2.

[0103] The surface of the Al-Mg welding wire in Example 1 was observed using an electron microscope, and the results are shown below. Figure 1 As can be seen, the surface of the welding wire has no obvious scratches, pits, or other obvious defects. A photograph of the welded joint in Example 1 is shown below. Figure 2 As can be seen, the weld formation is good, with no obvious defects such as incomplete fusion or incomplete penetration. The engineering stress-strain curve of the welded joint (weld wire deposited metal) in Example 1 is shown below. Figure 3 It can be seen that the tensile strength of the welded metal can reach 330MPa.

[0104] Test method:

[0105] Strength of Al-Mg welding wire: GB / T 228.1-2021 Metallic materials - Tensile testing - Part 1: Test method at room temperature.

[0106] Strength of weld metal and stress-strain curve: GB / T 228.1-2021 Metallic materials - Tensile testing - Part 1: Test method at room temperature.

[0107] Weld grade: CB / T 3747-2013 "Quality requirements for marine aluminum alloy welded joints".

[0108] Table 1

[0109]

[0110] Table 2

[0111]

[0112] As can be seen from the above, compared with the comparative example, the embodiments of the present invention control the alloy composition and use homogenization treatment and extrusion process to make the alloy elements uniformly distributed, effectively eliminating component segregation, resulting in welding wire with higher strength and improved wire processing performance; at the same time, by adopting a reasonable wire processing technology and controlling the composition of the rolling emulsion, the surface quality of the welding wire is improved, making its surface smooth, flat and free of scratches. The finished welding wire prepared can ensure stable combustion of the arc and molten pool during the welding process, thereby reducing defects such as weld porosity and effectively improving weld quality.

[0113] Furthermore, it can be seen that the overall effect is better when all process parameters are within the preferred range of the present invention.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an Al-Mg welding wire, characterized in that: The Al-Mg welding wire comprises, by weight percentage, Si≤0.05%, Fe≤0.12%, Cu≤0.01%, Mn≤0.55%, 5.6%≤Mg≤6.6%, Ti≤0.08%, and the balance is Al and unavoidable impurity elements, single impurity≤0.05%, and total impurity≤0.15%; the preparation method comprises the following steps: Step S1, melting and casting the alloy raw materials according to the composition ratio to obtain aluminum alloy cast rods; Step S2, homogenizing the aluminum alloy cast rod to obtain an aluminum alloy billet; Step S3, extruding the aluminum alloy billet to obtain an aluminum alloy extruded rod; Step S4, performing hot rough rolling on the aluminum alloy extruded rod, wherein the hot rough rolling also uses a hot rough rolling emulsion to obtain a hot rough rolled wire rod; Step S5, performing hot finish rolling on the hot rough rolled wire rod, wherein the hot finish rolling also uses a hot finish rolling emulsion to obtain a hot finish rolled wire rod; Step S6, drawing the hot-rolled wire to obtain a drawn wire; Step S7, coiling the drawn wire to obtain the Al-Mg welding wire; The mass concentration of the hot rough rolling emulsion is greater than the mass concentration of the hot finishing rolling emulsion, and the pH of the hot rough rolling emulsion is less than the pH of the hot finishing rolling emulsion.

2. The preparation method according to claim 1, characterized in that: The mass concentration of the hot rough rolling emulsion is 7-10%, and the pH value is 6-7; and / or The mass concentration of the hot finishing emulsion is 6-6.9%, and the pH value is 7.1-8.

3. The preparation method according to claim 1 or 2, characterized in that: Respectively and independently, in parts by weight, the hot rough rolling emulsion and the hot finishing rolling emulsion include 50-70 parts of mineral oil, 10-15 parts of trimethylol oleate, 5-10 parts of aliphatic hydrocarbons, 5-8 parts of dihydrated benzyldimethyltetradecylamine, 3-6 parts of ethoxylated fatty alkylamine, 3-5 parts of sodium petroleum sulfonate, 1-3 parts of N,N-dimethyldodecylamine N-oxide and 0.1-0.5 parts of phenolic antioxidant.

4. The preparation method according to claim 1 or 2, characterized in that: The starting rolling temperature of the hot rough rolling is 500-530°C; and / or the starting rolling temperature of the hot finish rolling is 400-440°C.

5. The preparation method according to claim 1 or 2, characterized in that: In step S6, the drawing also uses drawing oil, and the viscosity of the drawing oil is 90-110 mm 2 / s, density is 0.8~1.0g / cm 3 .

6. The preparation method according to claim 5, characterized in that: In parts by weight, the wire drawing oil comprises 20 to 30 parts of mineral oil, 40 to 50 parts of polyisobutylene, 15 to 25 parts of fatty acid ester, 10 to 15 parts of pentaerythritol ester and 1 to 3 parts of aniline antioxidant.

7. The preparation method according to claim 1 or 2, characterized in that: The casting temperature is 720-760°C; and / or The homogenization temperature is 450-500° C., and the insulation time is 10-24 hours.

8. An Al-Mg welding wire, characterized in that: The method according to any one of claims 1 to 7 is used to obtain the composition.

9. The Al-Mg welding wire according to claim 8, characterized in that: The strength of the Al-Mg welding wire is 450-500 MPa, and the strength of the deposited metal is 300-340 MPa.

10. A welding joint, characterized in that: The Al-Mg series welding wire according to claim 8 or 9 is used to weld with 5XXX series plates, and the weld grade is Grade I.

Images