A welding wire for aluminum-lithium alloy T-shaped structure and its preparation method and application

Abstract

The present invention relates to a welding wire for an aluminum-lithium alloy T-shaped structure and a preparation method and application thereof, and relates to the field of welding materials. The welding wire is in a strip shape, and its cross section is circular, elliptical or quasi-circular; the welding wire comprises a core regulating alloy, and the surface of the core regulating alloy is covered with a melt-resistant alloy. The welding wire can effectively solve the problem that multiple beneficial regulating elements of the welding wire are burned too quickly and unevenly distributed in the fillet weld during laser welding, and finally achieve the purpose of improving the comprehensive mechanical properties of the laser weld of the aluminum-lithium alloy T-shaped structure.

Description

Technical Field

[0001] The invention relates to the field of welding materials, and in particular to a welding wire for an aluminum-lithium alloy T-shaped structure and a preparation method and application thereof. Background Art

[0002] T-shaped structural parts made of aluminum-lithium alloy and aluminum alloy have been widely used in aircraft fuselage panels, high-speed train bodies, space launch vehicles and other major national equipment. T-shaped structures are generally composed of skins and long stringers. Since the two parts of the material need to be connected by rivets, the long stringers need to be designed into a Z shape to install rivets, such as Figure 1 This conventional design greatly increases the weight of the T-shaped structure, which is disadvantageous to the speed, carrying capacity and energy consumption of airplanes, trains and spacecraft.

[0003] Using laser welding technology instead of traditional riveting technology can not only get rid of heavy rivets, but also greatly simplify the T-shaped structure, achieve structural weight reduction, improve vehicle performance, and effectively promote energy conservation and emission reduction. At present, laser welding of aluminum-lithium alloys still uses Al-Si welding wires such as ER4047 or ER4043 to suppress weld porosity and crack defects, but with the increase in the types of alloying elements in new aluminum-lithium alloys, the grain boundary segregation problem has become more serious, and the types and quantities of intermetallic compounds formed on the grain boundaries have increased. The previous welding wire composition has been difficult to properly solve the increasingly complex defects in the weld. Summary of the invention

[0004] In view of the above problems, the present invention provides a welding wire for an aluminum-lithium alloy T-type structure, which can effectively solve the problem of rapid burning of various beneficial regulating elements of the welding wire and uneven distribution in the fillet weld during laser welding, and ultimately achieve the purpose of improving the comprehensive mechanical properties of the laser weld of the aluminum-lithium alloy T-type structure.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a welding material for an aluminum-lithium alloy T-type structure, the welding wire is in a strip shape, and the cross-section is circular, elliptical or quasi-circular; the welding wire includes a core regulating alloy, and the surface of the core regulating alloy is covered with a melt-resistant alloy.

[0006] In response to the above technical problems, the inventors discovered during the research process that the fan-shaped molten pool flow field during laser welding of aluminum-lithium alloy T-shaped structures is significantly different from the funnel-shaped molten pool of conventional butt joints, which makes it difficult for alloy elements in the welding wire to enter the center and bottom of the fan-shaped molten pool through the molten pool flow field, and ultimately causes pores and crack defects to form first in the center or bottom of the molten pool. Therefore, it is necessary to change the original welding wire structure and innovatively propose a new type of welding wire to solve the practical problem that the regulating elements in the welding wire cannot smoothly enter the center and bottom of the fan-shaped molten pool. Based on this, the inventors proposed a welding wire with the above structure, the outer contour of the cross section of the welding wire is circular, elliptical or quasi-circular, and the cross section of the welding material is composed of a resistant alloy located in the outermost layer and a core regulating alloy located in the central area. The melt-retardant alloy can delay the melting rate of the core regulating alloy by the laser beam energy, resulting in that the core regulating alloy will not be completely melted when the welding wire enters the molten pool, so that the core regulating alloy part of the welding wire can still have a certain strength and directionality at the moment it enters the molten pool, and the alloy material that is not completely melted can enter the center and bottom area of ​​the fan-shaped molten pool, resulting in more key regulating elements such as silicon, lanthanum, and europium being sent to the center and bottom of the molten pool, which can effectively solve the problem that the regulating elements in the welding wire cannot smoothly enter the center and bottom of the fan-shaped molten pool, effectively improve the chemical element distribution, grain structure and strength of the center and bottom of the T-shaped structure laser weld, and inhibit the initiation and expansion of microcracks from the center and bottom of the weld.

[0007] In one of the embodiments, the resistance alloy includes Al and / or Si, and the core control alloy includes Si, Cu, Mn, Ti, Zr, Zn, Mg, La and Eu.

[0008] The inventors have also improved the chemical composition of the welding wire, further refined the structure, and used the above elements to prepare the resistant alloy and the core control alloy. The Mg element is introduced into the core control alloy. The melting points of aluminum and magnesium are similar. When the magnesium element is added to the aluminum alloy, the melting point can be lowered, making the aluminum alloy easier to melt. In addition, the magnesium element can also promote the fluidity of the molten pool, which is conducive to the formation of the welded joint; pores are easily generated during the welding process of aluminum alloys. This is mainly because the surface of the aluminum alloy is easily oxidized, and the oxides will hinder the emission of gases. The addition of magnesium elements can react with oxides to eliminate oxides, thereby effectively preventing the generation of pores; magnesium elements can form a stable compound with aluminum: Mg2Al3, which has very high strength and can effectively improve the strength of aluminum alloys. At the same time, the appropriate addition of composite rare earth elements La and Eu can effectively refine the weld grains, promote the formation of equiaxed dendrites, and inhibit the formation of coarse columnar crystals and thermal cracks.

[0009] In one embodiment, the melt-resistant alloy includes the following raw materials in percentage by mass:

[0010] Si 0-6.50%

[0011] Al Residue.

[0012] In one embodiment, the core control alloy includes the following raw materials in percentage by weight:

[0013]

[0014] In one embodiment, the welding wire comprises the following raw materials in percentage by mass:

[0015]

[0016] The present invention also provides a method for preparing the welding wire, comprising the following steps: weighing raw materials, smelting, hot rolling to obtain a resistant alloy plate and a core regulating alloy column, rolling the resistant alloy plate to cover the surface of the core regulating alloy column, hot extruding, and drawing to obtain the welding wire.

[0017] The above preparation method is simple, efficient and easy to master, and only includes the steps of weighing, smelting, hot rolling, rolling, hot extrusion and drawing. Among them, the key hot rolling and rolling processes can be achieved using a conventional rolling platform, and the operation process is simple and the process repeatability is good.

[0018] In one embodiment, the temperature of the hot rolling is 120-180°C, the temperature of the rolling is 180-300°C, and the temperature of the hot extrusion is 150-200°C.

[0019] The present invention also provides application of the welding wire in preparing T-shaped structure aluminum-lithium alloy.

[0020] The present invention also provides a T-shaped aluminum-lithium alloy, the weld of which is welded by the welding wire.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention discloses a welding wire for an aluminum-lithium alloy T-shaped structure, a preparation method and an application thereof. The welding wire can effectively solve the problem that a variety of beneficial regulating elements of the welding wire are burned out too quickly and are unevenly distributed in the fillet weld during laser welding, and ultimately achieves the purpose of improving the comprehensive mechanical properties of the laser weld of the aluminum-lithium alloy T-shaped structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the riveting structure of the aircraft fuselage wall panel in the background technology;

[0024] Figure 2 Schematic diagram of the cross-sectional structure of the novel welding wire in Example 1, wherein 1 is the core regulating alloy and 2 is the resistance melting alloy;

[0025] Figure 3 Schematic diagram of the hot rolling process in Example 1, wherein (a) is the rolling process of the resistant melting alloy; (b) is the rolling process of the core regulating alloy, 1 is the core regulating alloy, 2 is the resistant melting alloy, 3 is the heated rolling wheel, 4 is the heating platform, and 5 is the heated rolling head;

[0026] Figure 4 Schematic diagram of the hot rolling process in Example 1, wherein 1 is the core control alloy, 2 is the refractory alloy, 4 is the heating platform, and 5 is the heating rolling head;

[0027] Figure 5 Schematic diagram of the hot extrusion and drawing composite forming process in Example 1, wherein 1 is the core control alloy, 2 is the resistant melting alloy, 6 is the heating extrusion cylinder, and 7 is the welding wire;

[0028] Figure 6 This is the microstructure diagram of the laser weld obtained in Example 2;

[0029] Figure 7 This is the electron probe scanning result of Eu rare earth element in the laser weld of Example 2;

[0030] Figure 8 This is the microstructure diagram of the laser weld obtained in Comparative Example 1;

[0031] Fig. 9 This is the electron probe scanning result of the laser weld of Comparative Example 1;

[0032] Fig.10 This is the microstructure diagram of the laser weld obtained in Comparative Example 2;

[0033] Fig.11 This is the electron probe scanning result of the laser weld in comparative example 2. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] source:

[0037] Unless otherwise specified, the reagents, materials, and equipment used in this example are all commercially available; the experimental methods are all conventional experimental methods in the art unless otherwise specified.

[0038] Example 1

[0039] A welding wire for an aluminum-lithium alloy T-shaped structure and a preparation method thereof.

[0040] 1. Configuration and raw materials of welding wire.

[0041] In this embodiment, the welding wire is in strip shape with a circular cross section, and is composed of a refractory alloy located on the outer surface and a core control alloy located in the middle. The refractory alloy has the function of delaying the melting speed of the core control alloy by the laser energy, allowing more key control alloys to enter the center and bottom area of ​​the molten pool, thereby increasing the content of key control elements in the center and bottom area of ​​the laser weld. Figure 2 The figure shows the structure of the new welding wire. The cross section of the welding wire is circular, and the size can be described by two physical quantities H and T. The thickness of the resistance melting alloy is (HT) / 2, H is in the range of 0.50-2.00mm, and T is in the range of 0.40-1.90mm.

[0042] The chemical composition of the resistant alloy and the core control alloy is different. The resistant alloy can be composed of pure Al or Al-Si alloy, and the chemical composition (weight %) of this part of the material includes: Si 0-6.50, and the rest is Al. The core control alloy is composed of Si, Cu, Mn, Ti, Zr, Zn, Mg, and rare earth La and Eu elements. The chemical composition (weight %) of this part of the alloy material includes: Si 5.50-8.90, Cu 5.90-7.60, Mn 0.15-0.65, Ti 0.02-0.20, Zr 0.02-0.15, Zn 0.02-0.15, Mg0.01-0.10, La 0.25-1.30, Eu 0.25-1.30, and the rest is Al. The chemical composition (weight %) of the welding material as a whole includes: Si 5.70-7.25, Cu 5.60-6.25, Mn 0.10-0.55, Ti 0.02-0.12, Zr 0.02-0.10, Zn 0.05-0.12, La 0.15-1.25, Eu 0.15-1.25, and the rest is Al. The chemical composition (weight %) of the welding wire as a whole should be calculated and expressed by the following formula,

[0043]

[0044] Among them, ω S i、ω' Si ,ω" Siare the Si content (weight %) in welding wire, melting resistance alloy and core control alloy, ω t is the content of other elements in the core control alloy except Si (weight %), ρ1 and ρ2 are the densities of the resistant alloy and the core control alloy, V1 and V2 are the volumes of the resistant alloy and the core control alloy, L is the length of the welding wire, and the meanings of H and T are as follows: Figure 2 shown.

[0045] In this embodiment, the core control alloy contains composite rare earths La and Eu, which can significantly increase the number of nucleation particles such as Al3La and Al3Eu in the molten pool, thereby effectively promoting the formation of equiaxed dendrite grains, reducing the formation of directionally grown coarse columnar grains, improving the tensile strength of the weld and inhibiting the formation of intergranular crack defects.

[0046] The welding wire's resistant alloy and core control alloy both contain Si elements, which can form Al-Si divorced eutectic structure in the grain boundary at the solidification front of the molten pool, effectively fill the intergranular microcrack defects that have already initiated and restore the strength of the grain boundary, inhibiting the initiation and expansion of intergranular cracks. Among them, the Si element in the core control alloy can enter the center and bottom of the laser weld during the laser welding process, increasing the Si content in these areas. The formed Al-Si divorced eutectic, Si phase, and LiAlSi phase can inhibit the intergranular crack defects initiated in the center and bottom of the laser weld; the Si element in the resistant alloy is mainly distributed in the near-surface area of ​​the fillet weld, which is used to inhibit the intergranular crack defects initiated near the surface of the fillet weld.

[0047] The core control alloy of the welding wire contains Cu, Mn, Ti, Zr, Zn, and Mg elements, which can improve the fluidity of the alloy in the laser molten pool, promote the rapid floating and overflow of bubbles in the molten pool, and effectively inhibit the formation of residual porosity defects in the weld. In addition, these elements can assist La and Eu elements in strengthening the role of grain refinement, changing the composition of intergranular structure, and helping to improve the grain and grain boundary structure and mechanical properties of the weld.

[0048] 2. Preparation method of welding wire.

[0049] The preparation method of welding wire includes the steps of raw material weighing, smelting, hot rolling, hot rolling combination, hot extrusion, and drawing composite forming.

[0050] In this embodiment, the weighing process is to calculate the weight of the raw materials based on the optimized Al and Si elemental compositions (weight %), and use an analytical balance to weigh the raw materials of the resistance melting alloy; calculate the weight of each single raw material based on the optimized Al, Si, Cu, Mn, Ti, Zr, Zn, Mg, La, and Eu elemental compositions (weight %), and use an analytical balance to weigh the raw materials of the core control alloy.

[0051] The smelting process is to put all the weighed raw materials into a plasma smelting furnace for smelting and homogenization, and obtain the resistant alloy ingot and the core control alloy ingot respectively.

[0052] The hot rolling process is to heat the resistant alloy ingot and the core regulating alloy ingot to 120-180℃ respectively, and then use the rolling wheel to roll the resistant alloy ingot and the core regulating alloy ingot into a thin plate and a cylindrical shape. The hot rolling process is as follows: Figure 3 shown.

[0053] The hot rolling combination process is to first place the resistant alloy sheet on the platform, place the core regulating alloy cylinder on the resistant alloy sheet, heat the two alloys together to 180-300℃ to achieve adhesion, move the rolling action surface forward to roll the resistant alloy sheet onto the surface of the core regulating alloy cylinder, and the hot rolling combination process is as follows: Figure 4 shown.

[0054] The hot extrusion and drawing composite forming process is to place the rolled cylindrical alloy in the extrusion cylinder, heat the alloy to 150-200℃ through the inner wall of the cylinder, slowly extrude the cylindrical alloy through the piston, and synchronously draw the extruded wire through the rotation of the reel. The hot extrusion and drawing composite forming process is as follows Figure 5 shown.

[0055] Example 2

[0056] A welding wire was prepared according to the configuration and preparation method of Example 1.

[0057] In this embodiment, the welding wire is composed of a melting resistance alloy and a core regulating alloy, wherein the melting resistance alloy is an Al-Si alloy component, and the core regulating alloy is an Al-Si-Cu-Mn-Ti-Zr-Zn-Mg-La-Eu alloy component. This embodiment also provides a method for preparing a welding wire for laser welding of an aluminum-lithium alloy T-shaped structure, comprising the following steps:

[0058] 1. Weighing of raw materials.

[0059] Select Al, Si, Cu, Mn, Ti, Zr, Zn, Mg, La, and Eu single alloys with a purity of not less than 99.9% as raw materials; use an analytical balance to weigh the raw materials, according to the Si element content (weight %) of 6.0% in the resistance-melting alloy, according to the Si element content (weight %) of 7.5% in the core-controlled alloy, the Cu element content is 6.80%, the Mn element content is 0.25%, the Ti element content is 0.15%, the Zr element content is 0.10%, the Zn element content is 0.08%, the Mg element content is 0.08%, the Eu element content is 0.8%, the La element content is 0.8%, and the rest is Al element.

[0060] 2. Melting.

[0061] The weighed alloy raw materials are melted, and the Al and Si raw materials used for the resistance melting alloy are placed in a plasma melting furnace to obtain resistance and capacitance alloy ingots. During the melting process, the alloy materials need to be homogenized and argon gas is introduced into the furnace to prevent the alloy from being oxidized. The oxidation reaction will lead to weakened element activity and element content errors. The same melting method is used to successively put Al, Si, Cu, Mn, Ti, La, Eu, Zr, Zn, and Mg raw materials into the melting furnace to obtain core control alloy ingots.

[0062] 3. Hot rolling.

[0063] The refractory alloy ingot and the core control alloy ingot obtained in the smelting process are respectively Figure 3 The hot rolling process is performed by the methods in (a) and (b). When hot rolling the resistant alloy ingot, the resistant alloy ingot is first heated to 150°C by heating the rolling wheel and the heating platform, and the relative speed between the rolling wheel and the resistant alloy ingot is set to 0.6m / min. The rolling process is repeated multiple times, and the rolling amount each time is 0.001-0.003m. The number of rolling times is based on the set total rolling thickness, and the final thickness is 0.01m. When hot rolling the core to control the alloy ingot, first pass The core-regulated alloy ingot is heated to 150°C as a whole by overheating the rolling wheel and the heating platform, and the relative speed between the heated rolling head and the core-regulated alloy round ingot is set to 1.0m / min. The rolling process is repeated multiple times, with the pressing amount of 0.001-0.003m each time. The number of rolling times is based on the set total rolling amount. Finally, the diameter of the core-regulated alloy round ingot (i.e., the core-regulated alloy column) is 0.11m, and the ratio of the thickness of the resistant alloy plate after rolling to the diameter of the core-regulated alloy round ingot is 1:11.

[0064] 4. Roll.

[0065] The refractory alloy plates and core alloy round ingots obtained by hot rolling are Figure 4 The schematic method is to carry out the hot rolling process, place the resistant alloy plate on the heating platform, place the core regulating alloy round ingot on the resistant alloy plate, and place the heated rolling head on the core regulating alloy round ingot. The two parts of the alloy are heated to 220°C together through the heat transfer effect of the heating platform and the heated rolling head. The alloy remains stable and not easy to oxidize at this temperature. Start the heated rolling head, set the relative speed of the heated rolling head and the alloy assembly to 0.5m / min, so that the resistant alloy plate can be rolled and coated on the surface of the core regulating alloy round ingot, and use multiple repeated rolling and rolling processes, with a rolling amount of 0.0005m each time, and the number of rolling times is based on the set total rolling amount, so that the diameter of the combined alloy round ingot is 0.05m.

[0066] 5. Hot extrusion and drawing.

[0067] The combined alloy round ingot obtained by the hot rolling process is Figure 5 The schematic method is to place the composite alloy round ingot into a heated extrusion cylinder for hot extrusion and drawing composite forming process. Specifically, the composite alloy round ingot is heated to 280°C as a whole through heat conduction of the heated extrusion cylinder, and an extrusion pressure is applied to the heated composite alloy round ingot, and the extrusion pressure is set to 1000kg. The alloy is extruded from the tapered mouth of the extrusion cylinder to form a welding wire, and the minimum diameter of the tapered mouth is 1.2mm. A pulling force is applied to the extruded welding wire, and the pulling force is set to 100kg, so that the drawn welding wire has a straight shape.

[0068] 6. Testing.

[0069] The welding wire obtained by the hot extrusion and drawing composite forming process was subjected to a laser welding test of an aluminum-lithium alloy T-shaped structure. The laser power was set to 3000W, the welding speed was 10m / min, the thickness of the 2099 aluminum-lithium alloy plate constituting the T-shaped structure was 2mm, the angle between the welding material and the horizontal direction was 20.5 degrees, and the feeding speed of the welding material was 2.8m / min.

[0070] The microstructure of the laser weld obtained by welding is as follows Figure 6 As shown in the figure, under the protection of the melting resistance alloy on the outer layer of the welding wire, the composite rare earth elements in the core control alloy can fully enter the interior of the laser weld, and the columnar crystals in the center of the laser weld are refined into equiaxed dendrites, effectively improving the mechanical properties of the laser weld. The electron probe (EPMA) scanning results of Eu elements in the laser weld are shown in the figure. Figure 7 As shown in the figure, the presence of Eu rare earth element can be detected in the center and bottom of the laser weld.

[0071] Comparative Example 1

[0072] The welding wire of this comparative example is only composed of a core regulating alloy without a melt-resistant alloy structure, and the core regulating alloy is an Al-Si-Cu-Mn-Ti-Zr-Zn-Mg-La-Eu alloy composition. The following steps are included:

[0073] 1. Weighing of raw materials.

[0074] Select Al, Si, Cu, Mn, Ti, Zr, Zn, Mg, La, and Eu single alloys with a purity of not less than 99.9% as raw materials; use an analytical balance to weigh the raw materials, and adjust the Si element content (weight %) in the alloy to 7.2%, the Cu element content to 6.60%, the Mn element content to 0.22%, the Ti element content to 0.12%, the Zr element content to 0.08%, the Zn element content to 0.05%, the Mg element content to 0.08%, the Eu element content to 0.75%, the La element content to 0.75%, and the rest to be Al element.

[0075] 2. Melting.

[0076] The weighed alloy raw materials are melted, and the Al, Si, Cu, Mn, Ti, La, Eu, Zr, Zn, and Mg raw materials are successively put into a plasma melting furnace to obtain core-controlled alloy ingots. During the melting process, the alloy materials need to be homogenized and argon gas is introduced into the furnace to prevent the alloy from being oxidized. The oxidation reaction will lead to weakened element activity and element content errors.

[0077] 3. Hot rolling.

[0078] The core alloy ingot obtained during the smelting process is regulated according to Figure 3 (b) The method in the hot working rolling process is used. When hot working the core-controlled alloy ingot, the core-controlled alloy ingot is first heated to 150°C by heating the rolling wheel and the heating platform, and the relative speed between the heated rolling head and the core-controlled alloy round ingot is set to 1.0m / min. The rolling process is repeated multiple times, with the pressing amount each time being 0.001-0.003m. The number of rolling times is based on the set total rolling amount, and finally the diameter of the core-controlled alloy round ingot is 0.12m.

[0079] 4. Hot extrusion and drawing.

[0080] The core alloy round ingot obtained by hot rolling is cast according to Figure 5 The schematic method is to place the core-regulated alloy round ingot into a heated extrusion cylinder for a hot extrusion and drawing composite forming process. The core-regulated alloy round ingot is heated to 280°C as a whole through heat conduction in the heated extrusion cylinder. An extrusion pressure is applied to the heated core-regulated alloy round ingot, and the extrusion pressure is set to 1000kg. The alloy is extruded from the tapered mouth of the extrusion cylinder to form a welding wire, and the minimum diameter of the tapered mouth is 1.2mm. A pulling force is applied to the extruded welding wire, and the pulling force is set to 100kg, so that the drawn welding wire has a straight shape.

[0081] 5. Testing.

[0082] The welding wire obtained by the hot working extrusion and drawing composite forming process was used for laser welding test of aluminum-lithium alloy T-type structure. The laser power was set to 3000W, the welding speed was 10m / min, the thickness of 2099 aluminum-lithium alloy plate constituting the T-type structure was 2mm, the angle between the welding material and the horizontal direction was 20.5 degrees, and the feeding speed of the welding material was 2.8m / min.

[0083] The microstructure of the laser weld obtained by welding is as follows Figure 8As shown in the figure, without the protection of the welding wire melt-resistant alloy, the composite rare earth elements in the core control alloy failed to fully enter the center and bottom of the laser weld, and thick and straight columnar grains were still formed in the center and bottom of the laser weld. The mechanical properties of the laser weld will be significantly reduced, and the strength deterioration perpendicular to the growth direction of the columnar grains is particularly obvious. The EPMA scanning results of the laser weld are shown in the figure. Fig. 9 As shown, obvious microcrack defects can be seen in the central area of ​​the laser weld.

[0084] Comparative Example 2

[0085] 1. This comparative example uses commercial welding wire ER4047, with a Si content of 12% and the remainder being Al, and a welding wire diameter of 1.2 mm.

[0086] 2. Conduct laser welding test on aluminum-lithium alloy T-shaped structure, set laser power to 3000W, welding speed to 10m / min, thickness of 2099 aluminum-lithium alloy plate constituting T-shaped structure to 2mm, angle between welding wire and horizontal direction to 20.5 degrees, feeding speed of welding wire to 3.2m / min.

[0087] The microstructure of the laser weld obtained by welding is as follows Fig.10 As shown in Figure 1, without rare earth elements Eu and La to refine the grains, a large number of straight and coarse columnar grains are formed in the laser weld. This columnar crystal structure cannot improve the mechanical properties of the laser weld. The electron probe EPMA scanning results of the laser weld are shown in Figure 1. Fig.11 As shown in the figure, without the effect of composite rare earth elements and melt-resistant alloy structure, the grain structure of laser weld is coarse, and obvious microcracks and porosity defects can be seen in the weld.

[0088] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A welding wire for aluminum-lithium alloy T-shaped structure, characterized in that: The welding wire is in strip shape, and its cross section is circular, elliptical or quasi-circular; the welding wire comprises a core regulating alloy, and the surface of the core regulating alloy is covered with a resistant melting alloy; The fusion-resistant alloy comprises the following raw materials in mass percentage: 0<Si content≤6.50%, Al is the balance; The core control alloy includes the following raw materials in percentage by mass: Si5.50-8.90% Cu5.90-7.60% Mn0.15-0.65% Ti0.02-0.20% Zr0.02-0.15％ Zn0.02-0.15% Mg0.01-0.10% La0.25-1.30% Eu0.25-1.30% Al Residue.

2. The welding wire according to claim 1, characterized in that The welding wire comprises the following raw materials in percentage by mass: Si5.70-7.25% Cu5.60-6.25% Mn0.10-0.55% Ti 0.02-0.12% Zr0.02-0.10％ Zn0.05-0.12% La0.15-1.25% Eu0.15-1.25% Al Residue.

3. The method for preparing the welding wire according to any one of claims 1 to 2, characterized in that: The following steps are involved: The raw materials are weighed, smelted, and hot rolled to obtain a resistant alloy plate and a core regulating alloy column. The resistant alloy plate is rolled and covered on the surface of the core regulating alloy column, and hot extruded and drawn to obtain a welding wire.

4. The preparation method according to claim 3, characterized in that: The temperature of the hot rolling is 120-180°C, the temperature of the rolling is 180-300°C, and the temperature of the hot extrusion is 150-200°C.

5. Use of the welding wire according to any one of claims 1 to 2 in the preparation of aluminum-lithium alloy T-shaped structural parts.

6. An aluminum-lithium alloy T-shaped structural member, characterized in that: The weld of the aluminum-lithium alloy T-shaped structural member is welded by the welding wire described in any one of claims 1-2.

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