An aluminum alloy welding wire and a preparation method and application thereof

Abstract

The application discloses an aluminum alloy welding wire and a preparation method and application thereof, and belongs to the technical field of welding wires.The aluminum alloy welding wire comprises the following components: 6.2-10.5 wt.% of silicon, 2.2-3.7 wt.% of magnesium, 0.1-2.0 wt.% of copper, 0.1-2.4 wt.% of manganese, 0.1-0.5 wt.% of zinc, 0.01-0.1 wt.% of strontium, ≤0.15 wt.% of iron and impurity elements, and the total amount of the welding wire is 100 wt.% by adjusting the content of aluminum; in a welding joint formed by welding using the aluminum alloy welding wire, the average hardness of the weld is greater than the average hardness of the welding heat-affected zone; in the preparation, the welding wire cast ingot is prepared first, and then the steps of homogenization treatment, hot extrusion, drawing and the like are carried out; experimental results show that when the aluminum alloy welding wire is used for welding the aluminum alloy, the weld has excellent mechanical properties, such as high strength and high hardness, and the welding joint coefficient is significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material welding, and in particular to an aluminum alloy welding wire and a preparation method and application thereof. Background Art

[0002] Aluminum alloys' advantages, such as low density, high specific strength, and high specific stiffness, have led to their widespread use in automotive, marine, and aerospace applications. This diverse range of applications requires diverse methods for joining aluminum alloy components. Fusion welding is the primary method for joining aluminum alloy components. In this process, appropriate filler materials are required to ensure that the weld joints possess sufficient strength and ductility to meet the service requirements of aluminum alloy structures, while minimizing weld defects such as porosity and thermal cracking.

[0003] Currently, the main 4XXX series (Al-Si series) aluminum alloy welding wires commonly used in industry are ER4043 and ER4047. ER4043 is a hypoeutectic Al-Si alloy widely used for welding 6XXX series aluminum alloys. Compared to ER4043, ER4047 is a eutectic Al-Si alloy with a lower melting point, a narrower solidification range, and better fluidity, resulting in relatively better overall welding performance. However, the mechanical properties of the welds produced by these two wires are strongly dependent on the composition of the diluted base material. The maximum strength of the welded joints can only reach approximately 70% of the strength of the 6XXX series aluminum alloy base material, and can even be as low as 50%, failing to meet the welding manufacturing requirements of high-end equipment. Summary of the Invention

[0004] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved aluminum alloy welding wire, wherein when the aluminum alloy welding wire is used to weld aluminum alloy, the weld has excellent mechanical properties, such as high strength, high hardness and high fatigue strength.

[0005] The present invention also provides a method for preparing the above-mentioned aluminum alloy welding wire and its application in laser welding, laser wire filling welding, laser-arc hybrid welding and additive manufacturing of aluminum alloy wire.

[0006] The present invention further provides an aluminum alloy product comprising a welded joint formed by the welding wire.

[0007] To achieve the above object, the present invention adopts a technical solution: an aluminum alloy welding wire, which comprises, by weight percentage:

[0008] 6.2 wt.% to 10.5 wt.% silicon (Si);

[0009] 2.2 wt.% to 3.7 wt.% magnesium (Mg);

[0010] 0.1 wt.% to 2.0 wt.% copper (Cu);

[0011] 0.1 wt.% to 2.4 wt.% manganese (Mn);

[0012] 0.1 wt.% to 0.5 wt.% zinc (Zn);

[0013] 0.01 wt.% to 0.1 wt.% of strontium (Sr);

[0014] Less than or equal to 0.15 wt.% of iron (Fe) and inevitable impurity elements, and the total amount of the aluminum alloy welding wire is 100 wt.% by adjusting the content of aluminum (Al);

[0015] In the welded joint formed by welding with the aluminum alloy welding wire, the average hardness of the weld is greater than the average hardness of the welding heat affected zone.

[0016] According to some specific aspects of the present invention, the welding is used to connect aluminum alloy parts.

[0017] According to the present invention, when the aluminum alloy welding wire is used to weld 6XXX series aluminum alloys, the magnesium content in the weld is 0.8wt.% to 1.5wt.%, Mg is fully dissolved in the weld and a small amount of Mg combines with Si to form a Mg2Si phase, so that the weld has high hardness.

[0018] According to some specific aspects of the present invention, the welding can be used for welding the same or different alloys among Al-Cu alloys, Al-Mg-Si alloys, Al-Zn alloys and Al-Si alloys.

[0019] According to some preferred aspects of the present invention, the average hardness of the weld in the weld joint is greater than the average hardness of the weld heat affected zone by more than 5 HV.

[0020] In some embodiments of the present invention, the average hardness of the weld in the weld joint can reach 98 HV or above.

[0021] According to some preferred aspects of the present invention, the structure of the weld includes an α-Al matrix, eutectic Si, an α-AlFeMnSi phase, a π-AlFeMgSi phase and a strip-shaped Mg2Si phase.

[0022] According to the present invention, the weld joint coefficient of the weld joint is greater than 75%.

[0023] In some embodiments of the present invention, the microstructure of the aluminum alloy welding wire includes an α-Al matrix, eutectic Si, an α-AlFeMnSi phase, a π-AlFeMgSi phase, and a skeleton Mg2Si phase;

[0024] The volume fraction of the α-Al matrix is ​​not less than 48%.

[0025] In some embodiments of the present invention, the aluminum alloy welding wire comprises, by weight percentage:

[0026] 7.0 wt.% to 10.0 wt.% silicon;

[0027] 2.6 wt.% to 3.5 wt.% magnesium;

[0028] 0.2 wt.% to 1.8 wt.% copper;

[0029] 0.1 wt.% to 2.0 wt.% manganese;

[0030] 0.1 wt.% to 0.2 wt.% zinc;

[0031] 0.01 wt.% to 0.1 wt.% of strontium;

[0032] The amount of iron and inevitable impurity elements is less than or equal to 0.15 wt.%, and the total amount of the aluminum alloy welding wire is 100 wt.% by adjusting the aluminum content.

[0033] Furthermore, the aluminum alloy welding wire comprises, by weight percentage:

[0034] 7.0 wt.% to 8.5 wt.% silicon;

[0035] 3.2 to 3.5 wt.% magnesium;

[0036] 1.5 wt.% to 1.8 wt.% copper;

[0037] 0.1 wt.% to 0.5 wt.% manganese;

[0038] 0.1 wt.% to 0.18 wt.% zinc;

[0039] 0.01 wt.% to 0.1 wt.% of strontium;

[0040] The amount of iron and inevitable impurity elements is less than or equal to 0.15 wt.%, and the total amount of the aluminum alloy welding wire is 100 wt.% by adjusting the aluminum content.

[0041] Another technical solution provided by the present invention is a method for preparing the aluminum alloy welding wire described above, the method comprising:

[0042] After selecting raw materials according to the component ratio, aluminum alloy welding wire ingots are made, and then homogenization treatment and hot extrusion are carried out to obtain aluminum alloy welding wire blanks; the obtained aluminum alloy welding wire blanks are drawn in multiple passes and subjected to multiple intermediate annealing treatments in the process to obtain aluminum alloy welding wires, which are then selectively surface treated.

[0043] In some embodiments, an intermediate annealing treatment is performed every time the drawing deformation reaches 45%-55%.

[0044] According to some preferred aspects of the present invention, the hardness of the aluminum alloy welding wire ingot is not less than 90 HV.

[0045] According to some preferred aspects of the present invention, the homogenization treatment is carried out by keeping the temperature at 500-550° C. for 8-15 hours.

[0046] According to some preferred aspects of the present invention, the temperature of the hot extrusion is 480-500°C.

[0047] According to some preferred aspects of the present invention, the number of drawing passes is 13-26, and the temperature of the intermediate annealing treatment is 400-430°C.

[0048] Another technical solution provided by the present invention is an application of the aluminum alloy welding wire described above in laser welding, laser wire-filling welding, laser-arc hybrid welding and additive manufacturing of aluminum alloy wires.

[0049] Another technical solution provided by the present invention is an aluminum alloy product, which includes at least two welding base materials and a welding wire for welding the at least two welding base materials together, wherein the welding wire includes the aluminum alloy welding wire described above.

[0050] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0051] Based on the defects of existing welding wires used for welding aluminum alloy parts, such as insufficient weld joint strength and welding defects (such as pores and thermal cracks), the present invention innovatively provides an improved aluminum alloy welding wire. By adjusting the formula, the present invention can control the average hardness of the weld in the weld joint formed by welding the aluminum alloy welding wire to be greater than the average hardness of the welding heat-affected zone. After the aluminum alloy welding wire of the present invention is welded to the base material, the strength of the weld joint can reach more than 75% of the corresponding base material strength, and can even reach about 85%, which is much higher than the existing highest weld joint coefficient of about 70%. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a physical picture of the aluminum alloy welding wire in Example 1 of the present invention;

[0053] Figure 2: is the as-cast structure diagram of the aluminum alloy welding wire ingot obtained in step S1 of Example 1 of the present invention;

[0054] Figure 3 : is the as-cast structure diagram of the aluminum alloy welding wire ingot obtained in step S1 in Example 2 of the present invention;

[0055] Figure 4 This is a cast microstructure diagram of the aluminum alloy welding wire ingot obtained in step S1 of Example 3 of the present invention;

[0056] Figure 5 This is a backscattered microstructure diagram of the weld center of the weld joint obtained by welding with aluminum alloy welding wire in Example 1 of the present invention;

[0057] Figure 6 This is a backscattered microstructure diagram of the weld center of the weld joint obtained by welding with aluminum alloy welding wire in Example 2 of the present invention;

[0058] Figure 7 This is a backscattered microstructure diagram of the weld center of the weld joint obtained by welding with aluminum alloy welding wire in Example 3 of the present invention;

[0059] Figure 8 This is the backscattered microstructure diagram of the weld center of the weld joint obtained after welding in Comparative Example 1;

[0060] Figure 9 This is the backscattered microstructure diagram of the weld center of the weld joint obtained after welding in Comparative Example 2;

[0061] Figure 10 This is the backscattered microstructure diagram of the weld center of the weld joint obtained after welding in comparative example 3;

[0062] Figure 11 The microhardness distribution diagram of the laser welded joints of Examples 1-3 at half the thickness of the plate;

[0063] Figure 12 The microhardness distribution diagram of the laser welded joints of Comparative Examples 1-3 along the half of the plate thickness;

[0064] Figure 13 This is a comparison chart of the average hardness of the welds of the laser welded joints of Examples 1-3 and Comparative Examples 1-3;

[0065] Figure 14 The engineering stress-strain curves of the laser welded joints of Example 1 and Comparative Examples 1-3 are shown;

[0066] Figure 15 The engineering stress-strain curve of the laser welded joint of Example 2-3. DETAILED DESCRIPTION

[0067] The aluminum alloy welding wire provided by the present application can exhibit excellent performance when welding aluminum alloy parts, for example, can greatly increase the average hardness of the weld in the formed welded joint, and exhibit the performance of the weld heat-affected zone after welding of the existing welding wire, which is superior to the weld, and the weld heat-affected zone of the aluminum alloy welding wire of the present application can become the lowest point of the performance of the welded joint; at the same time, surprisingly, the strength of the welded joint of the aluminum alloy welding wire of the present application after welding aluminum alloy parts such as 6XXX series aluminum alloy can reach more than 75% of the base material strength, even about 85%, which is much higher than the highest existing welded joint coefficient of about 70%.

[0068] The main idea of the present application is:

[0069] (1) The present application adds a specific content of Si in the aluminum alloy welding wire, which can avoid the problems of low welding strength and coarse weld structure in the use process, and can also avoid the problem that a large amount of Al-Si eutectic is enriched in the grain boundary of the welding wire, which is not conducive to the plasticity of the welded joint. In addition, it can also ensure that the welding wire has good fluidity and is easy to shape during preparation; in the welding process, the fluidity of the molten pool is good, which can inhibit the generation of solidification cracks and obtain a welded joint with good strength-plasticity matching and good shaping.

[0070] (2) The present application adds a specific content of Mg in the aluminum alloy welding wire, which can: ① ensure that enough Mg elements can be solid-solved in the Al matrix under high cooling speed during welding, thereby improving the strength of the welded joint; at the same time, avoid the performance decline caused by the reduction of the solid-solution amount of Mg in the weld due to the burning loss of Mg elements during welding. ② When welding high-strength 6XXX series aluminum alloy, the Mg content in the weld can be between 0.8wt.% and 1.5wt.%, Mg is fully solid-solved in the weld, and a small amount of Mg combines with Si to form Mg2Si phase, which ensures that the weld has high hardness. ③ The work hardening effect of the added Mg elements generates cyclic slip resistance at the crack tip, which hinders the propagation of the crack; a large number of slip systems are activated, and the solute Mg can change the crack motion into a non-localized mode, thereby resulting in a longer crack path before final failure and a longer fatigue life. ④ The welded joint can be heat-treated to obtain more excellent mechanical properties.

[0071] (3) The present application adds a specific content of Cu in the aluminum alloy welding wire, which can play a solid solution strengthening effect and will not precipitate Q phase and θ phase at the grain boundary, thereby avoiding reducing the corrosion resistance of the weld.

[0072] (4) The present invention adds a specific content of Mn to the aluminum alloy welding wire. Under the system of the present invention: when the Mg element in the weld reaches the solid solubility limit, the Mn element can further improve the weld performance through solid solution strengthening, and the Mn element has a high boiling point and is not easily burned during welding. The Al6Mn phase can dissolve the impurity Fe to form the Al6(Mn,Fe) phase, reducing the adverse effect of Fe on the ductility of the welding wire. The Al6Mn phase can inhibit the recrystallization process during the welding wire processing and increase the recrystallization temperature. After homogenization treatment, the fine-sized Al6Mn phase is dispersed, which can prevent grain boundary migration, thereby refining the grain size. In addition, a certain Mn content can also prevent mold sticking during the welding wire casting process.

[0073] (5) The present invention adds a specific content of Zn to the aluminum alloy welding wire. Under the system of the present invention, Zn is solid-dissolved in the aluminum matrix, thereby improving the solid-solution strengthening effect of the weld joint.

[0074] (6) The present invention adds a specific content of Sr to the aluminum alloy welding wire, which can modify the Al-Si alloy, spheroidize the needle-shaped eutectic Si, and improve the mechanical properties of the welding wire alloy.

[0075] In addition, the Al-Si welding wire of the present invention requires little heat input during welding, and when welding high-strength heat-treatable alloys, such as 2XXX series aluminum alloys, 6XXX series aluminum alloys, and 7XXX series aluminum alloys, the softening effect of the heat-affected zone caused is relatively low.

[0076] In some embodiments, the aluminum alloy welding wire or its intermediate aluminum alloy (eg, ingot, aluminum alloy melt, etc.) described in the present invention may have the elemental composition shown in Table 1.

[0077] Table 1

[0078] element Weight percentage (wt.%) Si 6.2～10.5 Mg 2.2～3.7 Cu 0.1～2.0 Mn 0.1～2.4 Zn 0.1～0.5 Sr 0.01～0.1 Fe ≤0.15 Al the remaining

[0079] The method for preparing the aluminum alloy welding wire provided by the present invention comprises the following steps:

[0080] S1. Prepare raw materials according to the set chemical composition of the welding wire and perform smelting and casting to obtain an aluminum alloy welding wire ingot; the raw materials are selected from high-purity metal aluminum, high-purity metal magnesium, high-purity metal copper and high-purity metal zinc and master alloys: aluminum-silicon master alloy, aluminum-manganese master alloy and aluminum-strontium master alloy;

[0081] S2. performing homogenization annealing on the ingot to obtain an aluminum alloy welding wire ingot; the homogenization annealing temperature is 500-550° C., and the holding time of the homogenization annealing is 8-15 hours;

[0082] S3. Remove the poorly formed parts at both ends of the ingot, peel it, and then hot extrude it to obtain an aluminum alloy welding wire billet; the hot extrusion temperature is 480-500°C, and the wire billet has a diameter of 6-9.5 mm;

[0083] S4, drawing the wire billet in multiple passes, performing an intermediate annealing treatment every time the drawing deformation reaches 50%, to obtain an aluminum alloy welding wire; the drawing passes are 13 to 26, and the intermediate annealing temperature is 400 to 430° C.;

[0084] S5. Clean the aluminum alloy welding wire to remove surface oil stains, dirt, etc. to obtain a finished welding wire; the diameter of the finished welding wire is 0.8 to 1.6 mm.

[0085] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0086] Unless otherwise specified in the following examples, all raw materials were purchased from commercial sources or prepared by conventional methods in the art.

[0087] In the following, "T5 heat treatment" refers to the state in which the aluminum alloy is cooled from the high-temperature forming process without undergoing cold working and then artificially aged.

[0088] Example 1:

[0089] This example provides an aluminum alloy welding wire and a preparation method thereof. In terms of weight percentage, the chemical composition of the aluminum alloy welding wire is: Si: 7wt.%, Mg: 2.6wt.%, Cu: 0.2wt.%, Mn: 0.1wt.%, Zn: 0.1wt.%, Sr: 0.03wt.%, Fe<0.15wt.%, and the remainder is Al and unavoidable impurity elements.

[0090] The preparation method of aluminum alloy welding wire comprises the following steps:

[0091] S1. Prepare raw materials according to the set chemical composition of the welding wire, and then smelt and cast them to obtain aluminum alloy welding wire ingots; the raw materials are high-purity metal Al, high-purity metal Mg, high-purity metal Cu and high-purity metal Zn and master alloys: Al-20Si master alloy, Al-10Mn master alloy and Al-10Sr master alloy.

[0092] S2. Perform homogenization annealing on the ingot to obtain an aluminum alloy welding wire ingot; the homogenization annealing temperature is 530° C., and the holding time of the homogenization annealing is 12 h.

[0093] S3. The poorly formed parts at both ends of the ingot are removed, and the ingot is peeled and then hot extruded to obtain an aluminum alloy welding wire billet; the hot extrusion temperature is 500° C., and a wire billet with a diameter of 9.5 mm is obtained.

[0094] S4. Drawing the wire billet in multiple passes, and performing an intermediate annealing treatment every time the drawing deformation reaches 50%, to obtain an aluminum alloy welding wire; the drawing passes are 16 times, and the intermediate annealing temperature is 410°C.

[0095] S5. Clean the aluminum alloy welding wire to remove surface oil stains, dirt, etc. to obtain a finished welding wire; the diameter of the finished welding wire is 1.2 mm.

[0096] The hardness of the aluminum alloy welding wire ingot was measured (test method: using XHVT-1000Z integrated micro Vickers hardness tester for measurement, with a load pressure of 1.96 N and a loading time of 15.0 s) to be 94.9±1.7 HV.

[0097] 3mm thick, T5 heat-treated Al-Mg-Si-Cu alloy profiles are selected as welding base materials. The specific composition is shown in Table 2:

[0098] Table 2 Chemical composition of Al-Mg-Si-Cu alloy

[0099] Si Mg Cu Cr Mn Ti Fe Zn Al 1.02wt.% 0.83wt.% 0.43wt.% 0.24wt.% 0.56wt.% 0.03wt.% 0.09wt.% 0.003wt.% margin

[0100] Two Al-Mg-Si-Cu test plates were descaled and laser butt-welded using a 1.2mm diameter aluminum alloy wire. The laser butt welding process parameters were: 2700W laser power, 50mm / s welding speed, circular laser beam oscillation with an amplitude of 0.6mm and a frequency of 100Hz. Post-weld observation revealed well-formed welds.

[0101] Example 2:

[0102] This example provides an aluminum alloy welding wire and a preparation method thereof. In terms of weight percentage, the chemical composition of the aluminum alloy welding wire is: Si: 9.05wt.%, Mg: 2.79wt.%, Cu: 1.23wt.%, Mn: 2wt.%, Zn: 0.13wt.%, Sr: 0.03wt.%, Fe<0.15wt.%, and the remainder is Al and unavoidable impurity elements.

[0103] The preparation method of aluminum alloy welding wire comprises the following steps:

[0104] S1. Prepare raw materials according to the set chemical composition of the welding wire, and then smelt and cast them to obtain aluminum alloy welding wire ingots; the raw materials are high-purity metal Al, high-purity metal Mg, high-purity metal Cu and high-purity metal Zn and master alloys: Al-20Si master alloy, Al-10Mn master alloy and Al-10Sr master alloy.

[0105] S2. Perform homogenization annealing on the ingot to obtain an aluminum alloy welding wire ingot; the homogenization annealing temperature is 520° C., and the holding time of the homogenization annealing is 14 h.

[0106] S3. Remove the poorly formed parts at both ends of the ingot, peel it, and then hot extrude it to obtain an aluminum alloy welding wire billet; the hot extrusion temperature is 490° C. to obtain a wire billet with a diameter of 9.5 mm.

[0107] S4. Drawing the wire billet in multiple passes and performing an intermediate annealing treatment every time the drawing deformation reaches 50% to obtain an aluminum alloy welding wire; the drawing passes are 18 times, and the intermediate annealing temperature is 415° C.

[0108] S5. Clean the aluminum alloy welding wire to remove surface oil stains, dirt, etc. to obtain a finished welding wire; the diameter of the finished welding wire is 1.2 mm.

[0109] The hardness of the aluminum alloy welding wire ingot was measured (test method: using XHVT-1000Z integrated micro Vickers hardness tester for measurement, with a load pressure of 1.96 N and a loading time of 15.0 s) to be 102±3.4 HV.

[0110] 3mm thick, T5 heat-treated 6061 aluminum alloy profiles are selected as welding base materials. The specific composition is shown in Table 3:

[0111] Table 3 Chemical composition of 6061-T5 aluminum alloy

[0112]

[0113]

[0114] Two 6061 aluminum alloy test plates were descaled and laser butt-welded using the prepared 1.2mm diameter aluminum alloy welding wire. The laser butt welding process parameters were: laser power 2700W, welding speed 50mm / s, circular laser beam oscillation with an amplitude of 0.6mm and an oscillation frequency of 100Hz. Post-weld observation revealed well-formed welds.

[0115] Example 3:

[0116] This example provides an aluminum alloy welding wire and a preparation method thereof. In terms of weight percentage, the chemical composition of the aluminum alloy welding wire is: Si: 7.70wt.%, Mg: 3.42wt.%, Cu: 1.75wt.%, Mn: 0.36wt.%, Zn: 0.12wt.%, Sr: 0.03wt.%, Fe<0.15wt.%, and the remainder is Al and unavoidable impurity elements.

[0117] The preparation method of aluminum alloy welding wire comprises the following steps:

[0118] S1. Prepare raw materials according to the set chemical composition of the welding wire, and then smelt and cast them to obtain aluminum alloy welding wire ingots; the raw materials are high-purity metal Al, high-purity metal Mg, high-purity metal Cu and high-purity metal Zn and master alloys: Al-20Si master alloy, Al-10Mn master alloy and Al-10Sr master alloy.

[0119] S2. Perform homogenization annealing on the ingot to obtain an aluminum alloy welding wire ingot; the homogenization annealing temperature is 500° C., and the holding time of the homogenization annealing is 15 hours.

[0120] S3. Remove the poorly formed parts at both ends of the ingot, peel it, and then hot extrude it to obtain an aluminum alloy welding wire billet; the hot extrusion temperature is 493° C. to obtain a wire billet with a diameter of 9.5 mm.

[0121] S4. Drawing the wire billet in multiple passes, and performing an intermediate annealing treatment every time the drawing deformation reaches 50%, to obtain an aluminum alloy welding wire; the drawing passes are 14 times, and the intermediate annealing temperature is 405° C.

[0122] S5. Clean the aluminum alloy welding wire to remove surface oil stains, dirt, etc. to obtain a finished welding wire; the diameter of the finished welding wire is 1.2 mm.

[0123] The hardness of the aluminum alloy welding wire ingot was measured (test method: using an XHVT-1000Z integrated micro Vickers hardness tester, with a load pressure of 1.96 N and a loading time of 15.0 s) to be 112±4.5 HV.

[0124] 3mm thick, T5 heat-treated 6082 aluminum alloy profiles are selected as welding base materials. The specific composition is shown in Table 4:

[0125] Table 4 Chemical composition of 6082-T5 aluminum alloy

[0126] Si Mg Cu Cr Mn Ti Fe Zn Al 0.90wt.% 0.67wt.% 0.04wt.% 0.01wt.% 0.49wt.% 0.03wt.% 0.09wt.% 0.003wt.% margin

[0127] Two 6082 aluminum alloy test plates were descaled and laser butt-welded using a 1.2mm diameter aluminum alloy wire. The laser butt welding process parameters were: 2700W laser power, 50mm / s welding speed, circular laser beam oscillation with an amplitude of 0.6mm and a frequency of 100Hz. Post-weld observation revealed well-formed welds.

[0128] Comparative Example 1:

[0129] The welding base material and the welding process are the same as those in Example 1, except that no welding wire is used during the welding process.

[0130] Comparative Example 2:

[0131] The welding base material and welding process are the same as those in Example 1, except that ER4047 welding wire produced by Lincoln Company of the United States is used in the welding process. The specific chemical composition of the wire is shown in Table 5.

[0132] Table 5 Chemical composition of ER4047 produced by Lincoln Company, USA

[0133] Si Mg Fe Mn Cr Cu Ti Zn Al 11.0wt.% <0.1wt.% 0.2wt.% <0.1wt.% <0.1wt.% <0.1wt.% <0.1wt.% <0.1wt.% margin

[0134] Note: Mg, Mn, Cr, Cu, Ti and Zn are not main components but impurities generated under manufacturing conditions.

[0135] Comparative Example 3:

[0136] The welding base material and welding process are the same as those in Example 1, except that ER5183 welding wire produced by Lincoln Company of the United States is used in the welding process. The specific chemical composition of the wire is shown in Table 6.

[0137] Table 6 Chemical composition of ER5183 produced by Lincoln Company, USA

[0138] Si Mg Fe Mn Cr Cu Ti Zn Al <0.4wt.% 5wt.% <0.4wt.% 0.5-1.0wt.% <0.1wt.% <0.1wt.% <0.15wt.% 0.25wt.% margin

[0139] Note: Cr, Cu and Ti are not main components, but impurities generated under manufacturing conditions.

[0140] Performance test results

[0141] (1) Figure 1 This is a physical picture of the aluminum alloy welding wire in Example 1 of the present invention;

[0142] Figure 2-Figure 4 They are the microstructure diagrams of the cast welding wire alloys of Examples 1 to 3, respectively. The microstructures of the cast welding wire alloys are mainly composed of α-Al matrix, eutectic Si, α-AlFeMnSi phase, π-AlFeMgSi phase and skeleton Mg2Si phase.

[0143] (2) Figure 5-Figure 7Figure 1 shows the microstructure of the weld center obtained by welding the aluminum alloy wire prepared in Examples 1-3. The weld structure mainly consists of α-Al matrix and eutectic Si, with bright white Fe-containing phase and a small amount of black Mg2Si phase at the grain boundaries.

[0144] The weld structure of Comparative Example 1-2 is composed of α-Al matrix, eutectic Si and bright white Fe-containing phase at the grain boundary. As the Si content in the welding wire increases, i.e. 0Si→11Si, the weld center structure ( Figure 8-Figure 9 ) The volume fraction of the precipitated phase in the weld metal increases significantly. Comparative Example 3 uses Al-Mg welding wire. During the welding solidification process, the Mg element dissolves in the α-Al matrix, and the weld structure consists of the α-Al matrix and the bright white Fe-containing phase ( Figure 10 ).

[0145] (3) Microhardness measurements were performed on each laser welded joint of Examples 1-3 and Comparative Examples 1-3 at half the thickness of the plate. The microhardness distributions obtained are shown in the following table. Figure 11 and Figure 12 As shown. The average hardness of the weld seam in Example 1 was approximately 98.2 HV, higher than the hardness of the over-aged heat-affected zone (~92.6 HV). The heat-affected zone is the lowest point in the weld joint's performance. Comparative Examples 1-3 all used the same base material as Example 1 for welding, and the lowest hardness point in each weld joint was the weld seam.

[0146] Figure 13 The figure is a comparison chart of the average hardness of the welds of various laser welded joints. The average hardness of the weld of the laser self-melting welded joint in Comparative Example 1 is the lowest. After the introduction of 5183 welding wire (Comparative Example 3), although the solid solution strengthening effect of the Mg element increases the average hardness of the weld, its contribution in this system is limited, and the average hardness is not improved enough. When using ER4047 welding wire (Comparative Example 2), although the volume fraction of the Si-containing precipitate phase in the weld is significantly increased, the hardness of the weld is significantly increased, but the gap with the present invention is still very significant, and the basic gap is 10HV or even more. The aluminum alloy welding wire provided by the present invention reduces the content of the Si element compared to the 4047 welding wire, and at the same time adds the Mg element to ensure that sufficient Mg element is solid-dissolved into the aluminum matrix under the rapid cooling conditions of the laser, and the remaining Mg element is precipitated in the form of Mg2Si. In addition, under the joint action of other components such as Mn and Cu, the aluminum alloy welding wire system of the present invention greatly improves the average hardness of the weld.

[0147] (4) Figure 14 and Figure 15 Room temperature tensile engineering stress-strain curves of each laser welded joint.

[0148] Calculations show that the tensile strength of the laser self-melting welding joint is the lowest, reaching only 64.6% of the tensile strength of the parent material. The comparison results are consistent with the average hardness of the weld. Based on the solid solution strengthening effect of the Mg element, the joint strength of the 5183 welding wire is improved compared to the laser self-melting welding joint. However, practice has found that the pores in the weld reduce the partial bearing capacity of the weld joint, so that its joint coefficient only reaches 66.4% of the parent material (Comparative Example 3). When using 4047 welding wire, the strength of the weld joint is further improved, reaching 72.8% of the parent material strength (Comparative Example 2). In contrast, the strength of the weld joint welded using the aluminum alloy welding wire provided by the present invention can reach 76.9% of the strength of the parent material (Example 1). Similarly, when the new aluminum alloy welding wire provided by the present invention is used to weld 6061-T5 and 6082-T5 deformed aluminum alloys, the strength of the weld joint can reach 80.7% (Example 2) and 84.9% (Example 3) of the corresponding parent material strength, respectively. The tensile properties of each laser welded joint are listed in Table 7.

[0149] Table 7 Tensile properties of laser welded joints

[0150] sample Yield strength (MPa) Tensile strength (MPa) Elongation after break (%) Joint coefficient (%) Example 1 225.5±5.9 301.3±7.7 1.5±0.1 76.9 Example 2 174.2±0.7 251.8±1.9 5.1±0.8 80.7 Example 3 199.9±1.4 279.4±1.4 2.5±0.1 84.9 Comparative Example 1 187.7±4.0 253.4±6.0 2.1±0.5 64.6 Comparative Example 2 211.7±1.5 285.2±4.8 1.6±0.2 72.8 Comparative Example 3 201.1±7.3 260.1±18.3 1.3±0.3 66.4

[0151] The above results show that the new aluminum alloy welding wire provided by the present invention can ensure that the weld has excellent mechanical properties (weld joint coefficient>75%), which is a significant improvement compared with the existing technology.

[0152] Note: Joint coefficient (%) = tensile strength of weld / tensile strength of base material × 100%;

[0153] The test standards for yield strength (MPa), tensile strength (MPa), and elongation at break (%) are GB / T 2651-2008.

[0154] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0155] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. An aluminum alloy welding wire, characterized in that: Measured in percentage by weight, the aluminum alloy welding wire comprises: 6.2 wt.% to 10.5 wt.% silicon; 2.2 wt.% to 3.7 wt.% magnesium; 0.1 wt.% to 2.0 wt.% copper; 0.1 wt.% to 2.4 wt.% manganese; 0.1 wt.% to 0.5 wt.% zinc; 0.01 wt.% to 0.1 wt.% of strontium; Less than or equal to 0.15wt.% of iron and inevitable impurity elements, the aluminum content is adjusted so that the total amount of the aluminum alloy welding wire is 100wt.%; The microstructure of the aluminum alloy welding wire includes an α-Al matrix, eutectic Si, an α-AlFeMnSi phase, a π-AlFeMgSi phase and a skeleton-like Mg2Si phase.

2. The aluminum alloy welding wire according to claim 1, characterized in that In the welded joint formed by welding with the aluminum alloy welding wire, the average hardness of the weld is greater than the average hardness of the welding heat affected zone.

3. The aluminum alloy welding wire according to claim 2, characterized in that The average hardness of the weld in the weld joint is greater than the average hardness of the weld heat affected zone by more than 5HV.

4. The aluminum alloy welding wire according to claim 1 or 2, characterized in that: When the aluminum alloy welding wire is used to weld 6XXX series aluminum alloys, the magnesium content in the weld is 0.8 wt.% to 1.5 wt.%.

5. The aluminum alloy welding wire according to claim 2, characterized in that The structure of the weld includes α-Al matrix, eutectic Si, α-AlFeMnSi phase, π-AlFeMgSi phase and strip-shaped Mg2Si phase.

6. The aluminum alloy welding wire according to claim 2, characterized in that The welding joint coefficient of the welding joint is greater than 75%.

7. The aluminum alloy welding wire according to claim 1, characterized in that In the organizational structure of the aluminum alloy welding wire, the volume fraction of the α-Al matrix is ​​not less than 48%.

8. The aluminum alloy welding wire according to claim 1, characterized in that Measured in percentage by weight, the aluminum alloy welding wire comprises: 7.0 wt.% to 10.0 wt.% silicon; 2.6 to 3.5 wt.% magnesium; 0.2 wt.% to 1.8 wt.% copper; 0.1 wt.% to 2.0 wt.% manganese; 0.1 wt.% to 0.2 wt.% zinc; 0.01 wt.% to 0.1 wt.% of strontium; The content of iron and inevitable impurities is less than or equal to 0.15 wt.%, and the total amount of the aluminum alloy welding wire is 100 wt.% by adjusting the aluminum content.

9. The aluminum alloy welding wire according to claim 8, characterized in that Measured in percentage by weight, the aluminum alloy welding wire comprises: 7.0 wt.% to 8.5 wt.% silicon; 3.2 to 3.5 wt.% magnesium; 1.5 to 1.8 wt.% copper; 0.1 wt.% to 0.5 wt.% manganese; 0.1 wt.% to 0.18 wt.% zinc; 0.01 wt.% to 0.1 wt.% of strontium; The content of iron and inevitable impurities is less than or equal to 0.15 wt.%, and the total amount of the aluminum alloy welding wire is 100 wt.% by adjusting the aluminum content.

10. A method for preparing the aluminum alloy welding wire according to any one of claims 1 to 9, characterized in that: The preparation method comprises: After selecting raw materials according to the component ratio, aluminum alloy welding wire ingots are made, and then homogenization treatment and hot extrusion are carried out to obtain aluminum alloy welding wire blanks; the obtained aluminum alloy welding wire blanks are drawn in multiple passes and subjected to multiple intermediate annealing treatments in the process to obtain aluminum alloy welding wires, which are then selectively surface treated.

11. The method for preparing the aluminum alloy welding wire according to claim 10, wherein: The hardness of the aluminum alloy welding wire ingot is not less than 90HV; and / or the homogenization treatment is heat preservation at 500-550°C for 8-15h; and / or the temperature of the hot extrusion is 480-500°C.

12. Use of the aluminum alloy welding wire according to any one of claims 1 to 9 in laser welding, laser filler wire welding, laser-arc hybrid welding and additive manufacturing of aluminum alloy wires.

13. An aluminum alloy product, characterized in that: The aluminum alloy product comprises at least two welding parent materials and a welding wire for welding the at least two welding parent materials together, wherein the welding wire comprises the aluminum alloy welding wire according to any one of claims 1 to 9.

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