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

Abstract

The present invention relates to a welding material for aluminum alloy T-shaped structure and its preparation method and application, and relates to the field of welding materials. The welding material can effectively refine weld grains, inhibit the generation of welding hot cracks and pore defects, effectively inhibit the initiation and expansion of hot cracks from inside the fillet weld, and ultimately improve the overall mechanical properties of the T-shaped structure aluminum alloy weld.

Description

Technical Field

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

[0002] There are a large number of aluminum alloy T-shaped structures in aircraft fuselages and high-speed rail bodies. Traditional processes mainly use riveting to connect the two parts of the aluminum alloy base material of the T-shaped structure. However, the use of rivets makes the structure of the aluminum alloy base material very complicated, and the weight of the T-shaped structure is greatly increased, which ultimately makes it difficult to achieve the weight reduction goals of aircraft and high-speed rail. The use of laser welding technology instead of traditional riveting is an innovation in manufacturing technology. The connection of aluminum alloy T-shaped structures is achieved by melting welding materials (referred to as welding materials) through laser beams, which can significantly simplify the structure of aluminum alloy base materials, effectively reduce the weight of aluminum alloy T-shaped structures, and improve the service performance limit of aircraft and high-speed rail. It has research significance and application value. However, when welding the fillet welds of aluminum alloy T-shaped structures with commonly used welding materials, defects such as microcracks and pores will exist, and these defects are not conducive to the overall mechanical properties of the T-shaped structure welds. Summary of the invention

[0003] In view of the above problems, the present invention provides a welding material for aluminum alloy T-shaped structures, which can effectively refine the weld grains, inhibit the generation of welding thermal cracks and porosity defects, effectively inhibit the initiation and expansion of thermal cracks from inside the fillet weld, and ultimately improve the overall mechanical properties of the T-shaped structure aluminum alloy weld.

[0004] In order to achieve the above object, the present invention provides a welding material for an aluminum alloy T-shaped structure, comprising a cladding alloy and a core control alloy, wherein the cladding alloy wraps the core control alloy;

[0005] The cladding alloy includes Al and / or Si; the core control alloy includes Si, Cu, Ti, Zr, Zn, Mn, Eu and La.

[0006] When studying laser welding of aluminum alloy T-shaped structures, the inventors found that due to the flow field characteristics of the laser molten pool, the alloy elements added to the welding material will be more concentrated in the near-surface area of ​​the fillet weld, and only a few alloy elements can enter the center and lower area of ​​the fillet weld under the action of the molten pool flow field. Figure 1The distribution characteristics of Si element in 4047 welding wire in aluminum alloy T-shaped structure fillet weld when the laser heat input is 16.8J / mm and 18J / mm respectively. The formation of defects such as microcracks and pores is caused by the lack of alloy elements in the center and bottom of the weld and the uneven distribution. The above defects are not conducive to the overall mechanical properties of the T-shaped structure weld. Therefore, the inventors propose a welding material composed of the above-mentioned component-coated alloy and core-regulated alloy, which can effectively refine the weld grains and inhibit the generation of welding hot cracks and pore defects by adding europium (Eu) and lanthanum (La) composite rare earth elements. At the same time, the core control alloy of the above-mentioned welding material is wrapped by the coating alloy, and the coating alloy can delay the melting speed of the core control alloy by the laser beam energy during welding, so that the core control alloy elements (such as silicon, europium, and lanthanum) that are not melted and have directionality on the surface of the molten pool can enter the center and bottom area of ​​the molten pool, thereby effectively improving the distribution of chemical elements in the center and bottom organization of the weld, making it more evenly distributed, and increasing the content of the core control alloy elements, effectively inhibiting the initiation and expansion of hot cracks from the inside of the fillet weld. The core control alloy contains Cu, Ti, Zr, Zn, and Mn elements, which can improve the fluidity of the liquid alloy in the molten pool, promote the rapid overflow of bubbles in the molten pool, and effectively reduce the generation of pore defects. In addition, these elements can assist rare earth elements in refining the grain structure, and at the same time, through the solid solution strengthening effect, change the chemical composition of the intermetallic compounds and divorced eutectic structures on the grain boundaries, and improve the strength and hardness level of the grain boundaries and grain structures.

[0007] In one embodiment, the cladding alloy includes the following raw materials in percentage by weight:

[0008] Si 0-5.20%

[0009] Al Residue.

[0010] In one embodiment, the cladding alloy includes the following raw materials in percentage by weight:

[0011] Si 1-5.20%

[0012] Al Residue.

[0013] In one embodiment, the core control alloy includes the following raw materials in percentage by weight:

[0014]

[0015] In one embodiment, the welding material includes the following raw materials in percentage by mass:

[0016]

[0017] In one embodiment, the surface of the core control alloy includes a front side and a back side, and the cladding alloy covers the front side and the back side.

[0018] In one embodiment, the front side is a plane, the back side is a plane, and the core control alloy is sandwiched between the cladding alloys.

[0019] When the two sides of the core regulating alloy are planes, the core regulating alloy is sandwiched between the cladding alloys to form a sandwich structure, and the welding material as a whole is in the shape of strips, sheets or plates.

[0020] The present invention also provides a method for preparing the welding material, comprising the following steps: weighing raw materials, smelting, cold rolling to obtain a cladding alloy and a core regulating alloy, covering the cladding alloy on the surface of the core regulating alloy, hot rolling, cutting, and obtaining the welding material.

[0021] The above-mentioned smelting step includes: putting the weighed raw materials into an arc smelting furnace for smelting and homogenization to obtain a coated alloy ingot and a core regulated alloy ingot, respectively. The above-mentioned cold rolling step includes: using a rolling wheel to roll the coated alloy ingot and the core regulated alloy ingot, respectively, to obtain a coated alloy and a core regulated alloy. The above-mentioned hot rolling step includes: after covering the surface of the core regulated alloy with the coating alloy, heating it to 180-300°C, and using a rolling wheel to roll the coated alloy and the core regulated alloy. The above-mentioned preparation method is simple, efficient and easy to master. The more critical cold rolling and hot rolling steps can be achieved through a conventional rolling platform, and the operation process is simple.

[0022] In one embodiment, the temperature of the hot rolling is 180-300°C.

[0023] The present invention also provides application of the welding material in preparing T-shaped structural aluminum alloy.

[0024] The present invention also provides a T-shaped structural aluminum alloy, the weld of which is welded by the welding material.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discloses a welding material for an aluminum alloy T-shaped structure, a preparation method and an application thereof. The welding material can effectively refine weld grains, inhibit the generation of welding thermal cracks and porosity defects, effectively inhibit the initiation and expansion of thermal cracks from inside the fillet weld, and ultimately improve the overall mechanical properties of the T-shaped structure aluminum alloy weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1The distribution characteristics of Si element in the fillet weld at different laser heat inputs, where a) the laser heat is 16.6 J / mm; b) the laser heat is 18 J / mm;

[0028] Figure 2 Schematic diagram of the cross-sectional structure of the welding material for the aluminum alloy T-shaped structure in Example 1, wherein 1 is the cladding alloy and 2 is the core control alloy;

[0029] Figure 3 Schematic diagram of the cold working and rolling process in Example 1, wherein 3 is a clad alloy ingot or a core regulated alloy ingot, 4 is a clad alloy plate or a core regulated alloy plate, 5 is a cold working and rolling wheel, and 6 is a platform;

[0030] Figure 4 Schematic diagram of the hot working combined rolling process in Example 1, wherein 6 is a platform, 7 is a cladding alloy plate, 8 is a core control alloy plate, 9 is a hot working rolling wheel, and 10 is a combined alloy plate;

[0031] Figure 5 This is the microstructure diagram of the fillet weld obtained in Example 2;

[0032] Figure 6 This is the electron probe scanning result of Eu rare earth element in the fillet weld of Example 2;

[0033] Figure 7 This is the microstructure diagram of the fillet weld obtained in Example 3;

[0034] Figure 8 This is the electron probe scanning result of Eu rare earth element in the fillet weld of Example 3;

[0035] Fig. 9 This is the microstructure diagram of the fillet weld obtained in Comparative Example 1;

[0036] Fig.10 This is the electron probe scanning result of Eu rare earth element in the fillet weld of comparative example 1;

[0037] Fig.11 This is the microstructure diagram of the fillet weld obtained in Comparative Example 2;

[0038] Fig.12 This is the electron probe scanning result of Si element in the fillet weld of comparative example 2. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] source:

[0042] 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.

[0043] Example 1

[0044] A welding material for an aluminum alloy T-shaped structure and a preparation method thereof.

[0045] 1. Configuration and raw materials of welding materials.

[0046] In this embodiment, the welding material is in the shape of a strip with a rectangular cross section. The welding material is composed of a core regulating alloy and a cladding alloy. The front and back sides of the core regulating alloy are flat, and the cladding alloy covers the front and back sides, so that the core regulating alloy is sandwiched between the cladding alloys. The cladding alloy has the effect of reducing the melting rate of the core regulating alloy by the laser energy, allowing more core regulating alloy to enter the center and bottom areas of the molten pool, effectively increasing the content of beneficial regulating elements in the center and bottom areas of the fillet weld. The structural schematic diagram of the welding material is shown in FIG. Figure 2 As shown, the cross-sectional dimensions of the welding material can be described by three physical quantities: W, H, and T. The thickness of the coating alloy is (HT) / 2, H is in the range of 1.00-2.00 mm, and W is in the range of 1.50-3.00 mm.

[0047] The cladding alloy can be composed of pure Al or Al-Si alloy, and the chemical composition (weight %) of this part of the material includes: Si0-5.20, and the rest is Al. The core control alloy is composed of Si, Cu, Ti, Zr, Zn, Mn and rare earth elements Eu and La. The chemical composition (weight %) of this part of the alloy material includes: Si 4.50-8.50, Cu 6.20-7.40, Ti 0.06-0.25, Zr0.06-0.30, Zn 0.06-0.20, Mn 0.06-0.20, Eu 0.15-1.50, La 0.15-1.50, and the rest is Al. The chemical composition (weight %) of the welding material as a whole includes: Si 5.20-7.30, Cu 6.00-6.90, Ti 0.05-0.15, Zr 0.05-0.15, Zn 0.05-0.10, Mn 0.05-0.10, Eu 0.10-1.20, La 0.10-1.20, and the rest is Al. The chemical composition (weight %) of the welding material as a whole should be calculated and expressed by the following formula:

[0048]

[0049] V1=(HT)·W·L (3)

[0050] V2=T·W·L (4)

[0051] Among them, ω Si ,ω′ Si ,ω″ Si are the Si content (weight %) in welding material, cladding alloy and core control alloy, ωt is the content of other elements except Si (weight %), ρ1 and ρ2 are the densities of cladding alloy and core control alloy, V1 and V2 are the volumes of cladding alloy and core control alloy, L is the length of welding material, and the representative meanings of H, T and W are as follows: Figure 2 shown.

[0052] In this embodiment, the core control alloy of the welding material contains composite rare earth Eu and La, which can significantly increase the number of nucleation particles at the solidification front of the molten pool, effectively reduce the formation of coarse columnar grains in the weld, and refine the grains, which is better than the case of adding Eu or La alone. At the same time, the cladding alloy and the core control alloy of the welding material contain Si elements, which can form Al-Si eutectic structure in the grain boundary at the solidification front of the molten pool, effectively fill the intergranular microcrack defects that have been initiated and restore the strength of the grain boundary, and inhibit the cracks from continuing to expand along the grain boundary. Among them, the Si element in the core control alloy mainly enters the center and bottom of the fillet weld to inhibit the microcrack defects initiated at the center and bottom of the fillet weld; the Si element in the cladding alloy is mainly distributed in the near-surface area of ​​the fillet weld to inhibit the microcrack defects initiated near the surface of the fillet weld. The core control alloy of the welding material contains Cu, Ti, Zr, Zn, and Mn elements, which can improve the fluidity of the liquid alloy in the molten pool, promote the rapid overflow of bubbles in the molten pool, and effectively reduce the generation of pore defects. In addition, these elements can assist rare earth elements in refining the grain structure. At the same time, through solid solution strengthening, they can change the chemical composition of intermetallic compounds and divorced eutectic structures on the grain boundaries, thereby improving the strength and hardness levels of grain boundaries and grain structures.

[0053] 2. Preparation method of welding materials.

[0054] The preparation method includes five steps: raw material weighing, smelting, cold rolling, hot rolling and cutting.

[0055] 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 coated alloy; calculate the weight of each single raw material based on the optimized Si, Cu, Ti, Zr, Zn, Mn, Eu, La, and Al elemental compositions (weight %), and use an analytical balance to weigh the raw materials of the core control alloy.

[0056] The smelting process is to put all the weighed raw materials into an arc melting furnace for smelting and homogenization to obtain the clad alloy ingot and the core control alloy ingot respectively.

[0057] The cold rolling process is to use a rolling wheel to roll the clad alloy ingot and the core control alloy ingot respectively. The thickness ratio of the clad alloy plate and the core control alloy plate after rolling is (HT) / 2T. The cold rolling process is as follows Figure 3 shown.

[0058] The hot rolling process is to pre-place two clad alloy plates on the upper and lower surfaces of the core control alloy plate, heat the three alloy plates to 180-300℃, and use a rolling wheel to roll the three alloy plates. The thickness of the combined alloy plate after rolling is H. The hot work combined rolling process is as follows: Figure 4The cutting process is to cut the combined alloy plate formed by hot combined rolling into uniform welding materials with a width of W.

[0059] Example 2

[0060] The welding material was prepared according to the configuration and preparation method of Example 1.

[0061] The welding material is composed of a cladding alloy and a core control alloy, wherein the cladding alloy is an Al-Si alloy component, and the core control alloy is an Al-Si-Cu-Ti-Zr-Zn-Mn-Eu-La alloy component. The specific preparation method is as follows.

[0062] 1. Weigh the raw materials.

[0063] Select Al, Si, Cu, Ti, Zr, Zn, Mn, Eu, and La 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 the coated alloy is 5.0%, and the balance is Al; according to the core control alloy, the Si element content (weight %) is 7.0%, the Cu element content is 6.50%, the Ti element content is 0.10%, the Zr element content is 0.20%, the Zn element content is 0.10%, the Mn element content is 0.14%, the Eu element content is 1.2%, the La element content is 1.2%, and the rest is Al element.

[0064] 2. Melting.

[0065] The weighed alloy raw materials are melted, and the Al and Si raw materials used for the coating alloy are put into a melting furnace to melt to obtain a coated alloy ingot. During the melting process, the alloy material needs to be homogenized, and argon gas is introduced into the furnace to prevent the alloy from being oxidized. Oxidation will lead to weakened element activity and element content errors. The same melting method is used to successively put Al, Si, Cu, Zn, Mn, Eu, La, Ti, and Zr raw materials into a melting furnace to melt to obtain a core controlled alloy ingot.

[0066] 3. Cold rolling.

[0067] The clad alloy ingot and the core control alloy ingot obtained by smelting are respectively Figure 3The schematic method performs a cold rolling process. When cold rolling the coated alloy ingot, the relative speed of the rolling wheel and the coated alloy ingot is set to 0.5m / min, and a repeated rolling process is used. The rolling amount each time is 0.002m, and the number of rolling times is based on the set total rolling thickness. The final thickness is 0.01m; when cold rolling the core-regulated alloy ingot, the relative speed of the rolling wheel and the core-regulated alloy ingot is set to 0.3m / min, and a repeated rolling process is used. The rolling amount each time is 0.0015m, and the number of rolling times is based on the set total rolling amount. The final thickness is 0.02m, and the ratio of the final thickness of the coated alloy plate and the core-regulated alloy plate after rolling is 1:2.

[0068] 4. Hot rolling.

[0069] The clad alloy plate and the core control alloy plate obtained by cold rolling are Figure 4 The schematic method is to carry out the hot rolling process, pre-place the two coated alloy plates on the upper and lower surfaces of the core control alloy plate, heat the support platform, hot working rolling wheel and the three-layer alloy plate assembly together to 220°C, the alloy remains stable and not easy to oxidize at this temperature, start the hot working rolling wheel, set the relative speed of the rolling wheel and the alloy plate assembly to 0.5m / min, use multiple repeated rolling processes, each rolling amount is 0.0005m, the number of rolling times is based on the set total rolling amount, and the final thickness H of the combined alloy plate is 0.0015m.

[0070] 5. Cutting.

[0071] The combined alloy plate obtained by hot rolling is cut, and the cutting width W is set to 0.002m, and finally a strip welding material with uniform width is obtained.

[0072] 6. Testing.

[0073] The laser welding test of aluminum alloy T-shaped structure fillet weld was carried out on the cut strip welding material. The laser power was set to 3100W, the welding speed was 11m / min, the thickness of the 2060 aluminum alloy plate constituting the T-shaped structure was 2mm, the angle between the welding material and the horizontal direction was 22 degrees, and the feeding speed of the welding material was 3.2m / min. The microstructure of the fillet weld obtained by welding is as follows: Figure 5 As shown in the figure, under the protection of the welding material coating alloy, the composite rare earth in the core control alloy can enter the interior of the fillet weld, forming a fine equiaxed grain structure at the center and bottom of the fillet weld, effectively improving the mechanical properties of the fillet weld. The electron probe (EPMA) scanning results of the Eu element in the fillet weld are shown in the figure. Figure 6 As shown in the figure, the presence of Eu rare earth element can be detected in the center and bottom of the fillet weld.

[0074] In this embodiment, both the coating alloy and the core control alloy contain Si element, which can form Al-Si eutectic structure in the grain boundaries 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 boundaries, thereby inhibiting the cracks from continuing to expand along the grain boundaries.

[0075] Example 3

[0076] The welding material was prepared according to the configuration and preparation method of Example 1.

[0077] The welding material is composed of a cladding alloy and a core control alloy, wherein the cladding alloy is a pure Al component and the core control alloy is an Al-Si-Cu-Ti-Zr-Zn-Mn-Eu-La alloy component. The specific preparation method is as follows.

[0078] 1. Weigh the raw materials.

[0079] Select Al, Si, Cu, Ti, Zr, Zn, Mn, Eu, and La 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 Al element content (weight %) in the coated alloy 100%; according to the core control alloy, the Si element content (weight %) is 8.5%, the Cu element content is 6.90%, the Ti element content is 0.18%, the Zr element content is 0.25%, the Zn element content is 0.14%, the Mn element content is 0.10%, the Eu element content is 1.4%, the La element content is 1.4%, and the rest is Al element.

[0080] 2. Melting.

[0081] The weighed alloy raw materials are smelted, and the pure Al raw material for the coating alloy is put into a smelting furnace to smelt to obtain a coated alloy ingot, and argon gas is introduced into the furnace to prevent the pure Al from being oxidized; the same smelting method is used to successively put Al, Si, Cu, Zn, Mn, Ti, Zr, Eu, and La raw materials into the smelting furnace to smelt to obtain a core controlled alloy ingot.

[0082] 3. Cold rolling.

[0083] The clad alloy ingot and the core control alloy ingot obtained by smelting are respectively Figure 3The schematic method performs a cold rolling process. When cold rolling the coated alloy ingot, the relative speed of the rolling wheel and the coated alloy ingot is set to 0.7m / min, and a repeated rolling process is used. The rolling amount each time is 0.005m, and the number of rolling times is based on the set total rolling thickness. The final thickness is 0.008m; when cold rolling the core-regulated alloy ingot, the relative speed of the rolling wheel and the core-regulated alloy ingot is set to 0.2m / min, and a repeated rolling process is used. The rolling amount each time is 0.001m, and the number of rolling times is based on the set total rolling amount. The final thickness is 0.024m, and the ratio of the final thickness of the coated alloy plate and the core-regulated alloy plate after rolling is 1:3.

[0084] 4. Hot rolling.

[0085] The clad alloy plate and the core control alloy plate obtained by cold rolling are Figure 4 The schematic method performs the hot rolling process, prefabricates two clad alloy plates on the upper and lower surfaces of the core control alloy plate, heats the support platform, hot working rolling wheel and three-layer alloy plate assembly together to 200°C, the alloy remains stable and not easy to oxidize at this temperature, starts the hot working rolling wheel, sets the relative speed of the rolling wheel and the alloy plate assembly to 0.3m / min, adopts multiple repeated rolling processes, each rolling amount is 0.0008m, the number of rolling times is based on the set total rolling amount, and the final thickness H of the combined alloy plate is 0.0015m.

[0086] 5. Cutting.

[0087] The combined alloy plate obtained by hot rolling is cut, and the cutting width W is set to 0.002m, and finally a strip welding material with uniform width is obtained.

[0088] 6. Testing.

[0089] The laser welding test of aluminum alloy T-shaped structure fillet weld was carried out on the cut strip welding material. The laser power was set to 3100W, the welding speed was 11m / min, the thickness of the 2060 aluminum alloy plate constituting the T-shaped structure was 2mm, the angle between the welding material and the horizontal direction was 22 degrees, and the feeding speed of the welding material was 3.2m / min. The microstructure of the fillet weld obtained by welding is as follows: Figure 7 As shown in the figure, fine equiaxed grain structure is also formed in the center and bottom of the fillet weld, which effectively improves the mechanical properties of the fillet weld. The electron probe scanning results of Eu element in the fillet weld are shown in the figure. Figure 8 As shown in the figure, the presence of Eu rare earth element can still be detected in the center and bottom area of ​​the fillet weld.

[0090] Comparative Example 1

[0091] The welding material of this comparative example is only composed of the alloy control alloy, and there is no cladding alloy structure. The core control alloy is Al-Si-Cu-Ti-Zr-Zn-Mn-Eu-La alloy composition. The specific preparation method is as follows.

[0092] 1. Weigh the raw materials.

[0093] Select Al, Si, Cu, Ti, Zr, Zn, Mn, Eu, and La 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 8.5%, the Cu element content to 6.90%, the Ti element content to 0.18%, the Zr element content to 0.25%, the Zn element content to 0.14%, the Mn element content to 0.10%, the Eu element content to 1.4%, the La element content to 1.4%, and the rest to Al element.

[0094] 2. Melting.

[0095] The weighed alloy raw materials are melted, and the raw materials for the core control alloy are put into a melting furnace in the order of Al, Si, Cu, Zn, Mn, Ti, Zr, Eu and La to obtain a core control alloy ingot, and argon gas is introduced into the furnace to prevent the alloy from being oxidized.

[0096] 3. Cold rolling.

[0097] The core alloy ingot obtained by smelting is cast according to Figure 3 The schematic method is used for the cold rolling process. When cold rolling the ingot, the relative speed between the rolling wheel and the ingot is set to 0.2m / min. The rolling process is repeated multiple times, with a rolling amount of 0.001m each time. The number of rolling times is based on the set total rolling amount, and the final thickness is 0.024m.

[0098] 4. Hot rolling.

[0099] The core regulated alloy plate obtained by cold rolling is subjected to a hot rolling process. The supporting platform, hot working rolling wheel and core regulated alloy plate are heated to 200°C together. The alloy remains stable and is not easily oxidized at this temperature. The hot working rolling wheel is started, and the relative speed between the rolling wheel and the alloy plate is set to 0.3m / min. The rolling process is repeated multiple times, with a rolling amount of 0.0008m each time. The number of rolling times is based on the set total rolling amount. The final thickness H of the alloy sheet is 0.0015m.

[0100] 5. Cutting.

[0101] The alloy sheet obtained by hot rolling is cut, and the cutting width W is set to 0.002m, and finally a strip welding material with uniform width is obtained.

[0102] 6. Testing.

[0103] The laser welding test of aluminum alloy T-shaped structure fillet weld was carried out on the cut strip welding material. The laser power was set to 3100W, the welding speed was 11m / min, the thickness of the 2060 aluminum alloy plate constituting the T-shaped structure was 2mm, the angle between the welding material and the horizontal direction was 22 degrees, and the feeding speed of the welding material was 3.2m / min. The microstructure of the fillet weld obtained by welding is as follows: Fig. 9 As shown in the figure, since the welding material has no outer layer of coating alloy protection, the laser energy will begin to melt the core regulating alloy before the welding material contacts the molten pool. At this time, the distribution of regulating elements is mainly affected by the flow field of the molten pool. Therefore, the rare earth elements Eu and La, which have the effect of refining grains, are difficult to enter the center and bottom of the molten pool. After the molten pool solidifies, a large number of straight columnar grains are formed, which has a significant adverse effect on the mechanical properties of the fillet weld. The electron probe scanning results of the Eu element in the fillet weld are shown in the figure. Fig.10 As shown in the figure, the intensity signal of Eu element is almost undetectable in the center and bottom area of ​​the weld, indicating that Eu element fails to smoothly enter the center and bottom area of ​​the fillet weld.

[0104] Comparative Example 2

[0105] 1. This comparative example uses commercial circular welding material ER4047, with a Si content of 12% and the remainder being Al, and a welding material diameter of 1.8 mm.

[0106] 2. Testing.

[0107] The laser welding of aluminum alloy T-shaped structure fillet weld was tested. The laser power was set to 3100W, the welding speed was 11m / min, the thickness of the 2060 aluminum alloy plate constituting the T-shaped structure was 2mm, the angle between the welding material and the horizontal direction was 22 degrees, and the feeding speed of the welding material was 3.2m / min. The microstructure of the fillet weld obtained by welding is shown in Figure 2. Fig.11 As shown in the figure, without the rare earth elements Eu and La to refine the grains, a large number of straight and coarse columnar grains are formed in the fillet weld. This columnar crystal structure cannot improve the mechanical properties of the fillet weld. The distribution characteristics of Si elements in the fillet weld are shown in the figure. Fig.12 As shown in the figure, without the effect of the cladding alloy, the Si element failed to completely enter the center and bottom of the fillet weld.

[0108] 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.

[0109] 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 material for aluminum alloy T-shaped structure, characterized in that: It includes a cladding alloy and a core control alloy, wherein the cladding alloy wraps the core control alloy; The cladding alloy comprises the following raw materials in percentage by mass: Si 0-5.20% Al remainder; The core control alloy includes the following raw materials in percentage by mass:

2. The welding material according to claim 1, characterized in that: The welding material includes the following raw materials in percentage by mass:

3. The welding material according to any one of claims 1 to 2, characterized in that: The surface of the core control alloy includes a front side and a back side, and the cladding alloy covers the front side and the back side.

4. The welding material according to claim 3, characterized in that The front side is a plane, the back side is a plane, and the core control alloy is sandwiched between the cladding alloys.

5. The method for preparing the welding material according to any one of claims 1 to 4, characterized in that: The following steps are involved: The raw materials are weighed, smelted, and cold rolled to obtain the cladding alloy and the core control alloy. The cladding alloy is covered on the surface of the core control alloy, hot rolled, and cut to obtain the welding material.

6. The preparation method according to claim 5, characterized in that: The temperature of the hot rolling is 180-300°C.

7. Use of the welding material according to any one of claims 1 to 4 in the preparation of T-shaped structural aluminum alloy.

8. A T-shaped structural aluminum alloy, characterized in that: The weld of the T-shaped structural aluminum alloy is welded by the welding material described in any one of claims 1-4.

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