Dissimilar metal welding device

Abstract

The present invention discloses a heterogeneous metal welding device, including a workbench, a welding gun, a welding wire, a stirring head, a metal plate A, and a metal plate B; the metal plate A and the metal plate B are arranged on the workbench in the form of a butt joint, and a prefabricated groove is arranged on the upper surface of the metal plate A; a groove is opened on the metal plate B; the welding gun and the welding wire are both arranged above the prefabricated groove on the metal plate A, the stirring head is arranged above the area to be welded between the metal plate A and the metal plate B, and the welding gun is located in front of the stirring head; during the welding process, the stirring head and the welding gun move in the same direction at the same speed. Through the above technical scheme, the thickness of the intermetallic compound layer of the weld is reduced, and its morphology is changed, and the residual stress of the joint is effectively released; through the prefabricated groove combined with the brazing-stir friction welding, the macro-micro welding and riveting composite connection of the heterogeneous metal plates is realized at the same time, and the mechanical properties of the joint are significantly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of material connection, and in particular relates to a heterogeneous metal welding device. Background Art

[0002] Heterogeneous metal welding refers to the process of welding two or more different metals (mainly those with large differences in chemical properties and thermophysical properties) under certain process conditions. Welded structural parts of heterogeneous metals can not only bring out the good properties of each parent material, but also reduce costs. However, heterogeneous metal welding also has many difficulties and pain points, and various technical bottlenecks need to be overcome to ensure welding quality and efficiency.

[0003] Taking aluminum alloy and copper as an example, the solid solubility of aluminum and copper in the solid state is limited and the thermal expansion coefficient is quite different. After welding, the joint is prone to produce a large amount of brittle intermetallic compounds and large residual stress, which seriously deteriorates the joint performance. The existing welding process cannot effectively solve the above problems, and the joint strength is difficult to guarantee.

[0004] The invention patent with application number CN201811078349.1 discloses an aluminum-copper heterogeneous metal TIG brazing process, which directly heats the copper by introducing a TIG arc, relies on the heat conduction of copper to melt the welding wire and form a molten pool, and feeds the welding wire at a constant speed at the same time, ultimately achieving aluminum-copper brazing. However, it should be pointed out that this process is difficult to accurately control the heat input of the joint, causing a certain degree of thermal damage to the copper. In addition, this method does not involve a solution to the problem of residual stress inside the weld.

[0005] The document "Study on microstructure and mechanical properties of Cu / Aljoints brazed by flux-cored Al–Si filler metal, F.Cai, L.Zhang, Y.Li, et al., Vacuum, 2022 201:111066." reported a brazing process of 3003 aluminum alloy and T2 copper. This method ensures the wettability of the brazing material to the base material by introducing a brazing flux, which will affect the corrosion resistance of the joint to a certain extent. At the same time, this method also fails to effectively release the residual stress of the joint. The shear strength of the aluminum-copper joint is 56MPa.

[0006] Taking aluminum alloy and titanium as an example, the aluminum-titanium composite structure has the advantages of aluminum's good ductility, low density and good processing formability and titanium's good high temperature resistance and strong corrosion resistance, and is widely used in many fields such as aerospace, navigation, automobiles, and rail transportation. However, the solid solubility of aluminum and titanium in the solid state is limited, and the thermal conductivity, thermal expansion coefficient, etc. are quite different. After welding, the joint is prone to produce a large amount of brittle intermetallic compounds such as TiAl and TiAl3 and large residual stress, resulting in low strength of the aluminum-titanium joint. Therefore, it is very important to choose a suitable welding method for connecting aluminum-titanium heterogeneous metals.

[0007] The literature "Influence of welding parameters on the IMCs and the mechanical properties of Ti / Al butt joints welded by MIG / TIG double-sided arc welding-brazing. Y. Zhang, J. Huang, Z. Ye, et al. Journal of Alloys and Compounds, 2018 747: 764-771" reported a method of realizing Ti / Al connection by MIG-TIG double-sided brazing. This process is difficult to control the heat input, and the heat distribution of the joint is uneven, resulting in different thicknesses of the intermetallic compounds at the interface. The area with too thick intermetallic compounds becomes the weak area of ​​the joint. In addition, this process does not mention an effective way to release the residual stress of the joint.

[0008] The invention patent with application number CN 202011026042.4 discloses a method for achieving heterogeneous welding of titanium alloy and aluminum alloy. In order to avoid the generation of Ti / Al brittle phase in the welding zone, Sn is used as the welding transition metal. By stir friction welding, a high-quality friction welding weld is obtained. However, it should be pointed out that the problem that the thickness of the aluminum-titanium joint obtained by this process is lower than the thickness of the parent material has not been effectively solved. In some application operations, the joint still needs to be processed secondary.

[0009] As a highly efficient solid-phase connection technology, friction stir welding has the advantages of low welding temperature, small deformation, few welding defects, and easy to obtain high-strength joints. However, in the actual operation process, a large amount of pressure must be introduced to ensure the performance of the joint, resulting in the joint thickness being significantly lower than the parent material thickness. In some application fields, the joint needs to be subjected to secondary machining, which increases the production process. In addition, friction stir welding usually requires a large axial force to ensure that sufficient friction heat is generated, which places certain requirements on the rigidity of the fixture.

[0010] It can be seen that in order to reduce the hazards of intermetallic compounds in heterogeneous metal welding joints, release the residual stress of the joints, and improve the strength of the welding joints, it is urgently necessary to develop a new welding device that is low-cost, simple to operate, and practical to improve the performance of heterogeneous metal welding joints and achieve high-performance connection of heterogeneous metal joints. Summary of the invention

[0011] In view of this, the present invention discloses a heterogeneous metal welding device, and the specific scheme is as follows:

[0012] It includes a friction stir welding machine and a brazing welding machine, wherein the friction stir welding machine includes a stirring head, and the brazing welding machine includes a welding gun, a workbench, a welding wire, a metal plate A, and a metal plate B;

[0013] The metal plate A and the metal plate B are arranged on a workbench in the form of a butt joint, the upper surface of the metal plate A is provided with a prefabricated groove, and the prefabricated groove extends along the direction of the weld; the metal plate B is provided with a groove;

[0014] The welding gun and welding wire are both arranged above the prefabricated groove on the metal plate A, the stirring head is arranged above the area between the metal plate A and the metal plate B, and the stirring head covers the prefabricated groove on the metal plate A and the groove on the metal plate B, the length direction of the weld between the metal plate A and the metal plate B is perpendicular to the plane formed by the central axis of the stirring head and the plane where the workbench is located, and the welding gun is located in front of the stirring head;

[0015] The specific time when the stirring head intervenes from the starting point of the area between the metal plate A and the metal plate B is: the liquid metal after the welding wire melts fills the prefabricated groove and then flows into the area between the metal plate A and the metal plate B to form the filling metal, and the stirring head intervenes when the filling metal is in a semi-solid state;

[0016] During the welding process, the stirring head and the welding gun move in the same direction at the same speed.

[0017] As a supplement to the technical solution of the present invention, the groove angle on the metal plate B is 30°-40°.

[0018] As a supplement to the technical solution of the present invention, the prefabricated grooves on the metal plate A are provided with one or more groups. When there are multiple groups of prefabricated grooves, the multiple groups of prefabricated grooves are parallel to each other and the distance between two adjacent groups of prefabricated grooves is 1-2 mm.

[0019] As a supplement to the technical solution of the present invention, when the prefabricated grooves are a group, the prefabricated grooves are dovetail groove structures.

[0020] As a supplement to the technical solution of the present invention, the prefabricated groove on the metal plate A is a continuous and uninterrupted groove structure.

[0021] As a supplement to the technical solution of the present invention, when a MIG welder is selected, the welding working parameters of the MIG welding are specifically as follows: the dry extension length of the MIG welding gun is set at 10-20 mm, the argon shielding gas flow rate is 18-22 L / min, the welding current is 20-200 A, the welding speed is 1.5-4 mm / s, and the wire feeding speed is 10-28 mm / s;

[0022] When a TIG welder is selected, the specific welding working parameters of TIG welding are: the distance between the tungsten tip of the TIG welding gun and the horizontal plane of the stainless steel plate is 0.5-2.5mm, the argon shielding gas flow rate is 18-22L / min, the welding current is 20-200A, the welding speed is 1.5-4mm / s, and the wire feeding speed is 10-28mm / s.

[0023] As a supplement to the technical solution of the present invention, the specific welding working parameters of the friction stir welding are: rotation speed 400-1500r / min, shoulder pressure 0.1mm, welding speed 1.5-4mm / s, stirring needle inclination angle 2°-2.5°.

[0024] As a supplement to the technical solution of the present invention, the friction stir welding adopts static shoulder friction stir welding.

[0025] As a supplement to the technical solution of the present invention, the metal plate A is a copper plate, and the metal plate B is an aluminum alloy plate.

[0026] As a supplement to the technical solution of the present invention, the metal plate A is a titanium alloy plate, and the metal plate B is an aluminum alloy plate.

[0027] Beneficial effects:

[0028] 1. The present invention achieves a composite connection through fusion welding / brazing and stir friction welding, breaking through the limitation of a single welding method and having a novel concept.

[0029] 2. Through the prefabricated groove on the metal plate A, use fusion brazing and stir friction welding to make the liquid metal formed after the fusion brazing melts the welding wire fill the prefabricated groove and then flow into the area between the metal plates A and B, forming a macroscopic welding and riveting composite connection.

[0030] 3. When the weld metal is in a semi-solid state, friction stir welding is used to break up brittle phases such as intermetallic compounds by large deformation, thereby reducing the compound thickness and refining the grain structure, while eliminating void defects inside the weld. In addition, the broken interface intermetallic compound layer exists in a serrated shape, forming a microscopic weld-riveted composite connection in situ.

[0031] 4. After the friction stir welding is introduced, the static shoulder of the stirring head reduces the peak temperature of the weld metal, improves the weld formation, and releases the residual stress inside the weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the present invention.

[0033] Figure 2 It is a schematic diagram of the side structure of metal plate A and metal plate B.

[0034] Figure 3 It is a schematic diagram of the side structure of metal plate A and metal plate B.

[0035] In the figure: 1. welding gun, 2. welding wire, 3. workbench, 4. stirring head, 5. welding direction, 6. metal plate A, 7. forming groove, 8. metal plate B, 9. prefabricated groove. DETAILED DESCRIPTION

[0036] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] like Figure 1 , Figure 2 As shown, the present invention discloses a heterogeneous metal welding device, including a friction stir welding machine and a brazing welding machine, wherein the friction stir welding machine includes a stirring head 4, and the brazing welding machine includes a welding gun 1, a workbench 3, a welding wire 2, a metal plate A6, and a metal plate B8;

[0039] The metal plate A6 and the metal plate B8 are arranged on the workbench 3 in the form of a butt joint, the upper surface of the metal plate A6 is provided with a prefabricated groove 9, and the prefabricated groove 9 extends along the direction of the weld; the metal plate B8 is provided with a groove. The angle of the groove on the metal plate B8 is 30°-40°.

[0040] The welding gun 1 is arranged above the prefabricated groove 9 on the metal plate A6, and the stirring head 4 is arranged above the area to be welded between the metal plate A6 and the metal plate B8, and the stirring head 4 covers the prefabricated groove 9 on the metal plate A6 and the groove on the metal plate B8. When the axial shoulder of the stirring head 4 of the friction stir welding covers the prefabricated groove 9, during the friction stir welding process, the static axial shoulder on the stirring head 4 compacts the metal in the prefabricated groove 9 of the stainless steel plate to ensure that the prefabricated groove 9 on the stainless steel plate is fully filled. At the same time, the stirring needle can release the stress of the metal in the prefabricated groove 9 on the stainless steel plate to solve the problem of stress concentration. Secondly, during the processing of the welding joint, the stirring needle can make the metal flow, so that it is dispersed more evenly to achieve a dispersed distribution effect, and can break up the intermetallic compounds of the welding joint, while reducing the thickness of the intermetallic compounds. The length direction of the weld between the metal plate A and the metal plate B is perpendicular to the plane formed by the central axis of the stirring head and the plane where the workbench is located. The welding gun 1 is located in front of the stirring head 4;

[0041] The specific time when the stirring head 4 intervenes from the starting point of the area between the metal plate A6 and the metal plate B8 is: the liquid metal after the welding wire 2 melts fills the prefabricated groove 9 and then flows into the area between the metal plate A6 and the metal plate B8 to form the filling metal, and the stirring head 4 intervenes when the filling metal is in a semi-solid state;

[0042] During the welding process, the stirring head 4 and the welding gun 1 move in the same direction at the same speed.

[0043] When two heterogeneous metal plates are welded by conventional fusion brazing, after welding, the residual stress near the welding joint area of ​​one of the metal plates is large and the intermetallic compound is thick. Under this condition, it is necessary to open a prefabricated groove 9 on the metal plate with large residual stress and thick intermetallic compound, and then use the welding structure disclosed in the present invention for welding. For example, if the residual stress near the welding joint area of ​​metal plate A is large and the metal compound is thick, it is necessary to open a prefabricated groove on metal plate A. The main reason for the above-mentioned large residual stress and thick intermetallic compound is that the chemical properties and thermophysical properties of heterogeneous metals are different.

[0044] In the present invention, fusion brazing is a welding method in which the interface of the high melting point side of the heterogeneous metal (such as steel, titanium, copper) is brazed, and the interface of the low melting point side (such as aluminum) is fusion welded. The welding method can be MIG, TIG, laser welding, or laser + TIG, laser + MIG or other welding methods, and is not limited to TIG welding or MIG welding disclosed in the present invention. Its main purpose is to melt the welding wire.

[0045] The present invention adopts molten brazing combined with stir friction welding to achieve a welding and riveting composite connection. The liquid metal after the welding wire 2 is melted fills the prefabricated groove 9 through the prefabricated groove 9 of the metal plate A6 and then flows into the area between the metal plate A6 and the metal plate B8. After welding, the metal in the prefabricated groove 9 is connected to the metal in the weld area to form a macro welding and riveting composite connection, thereby improving the strength of the welded joint.

[0046] When the weld metal is in a semi-solid state, friction stir treatment is used to break up brittle phases such as intermetallic compounds by large deformation, thereby reducing the thickness of the compound and refining the grain structure. In addition, the broken interface intermetallic compound layer exists in a serrated shape, forming a microscopic weld-riveted composite connection in situ.

[0047] Through the above technical scheme, the present invention reduces the thickness of the intermetallic compound layer and changes its morphology, effectively releasing the residual stress of the joint; in addition, large deformation drives plastic flow to prompt the weld metal to fill the macro-mechanical prefabricated groove 9 and form micro-interlocking in situ, ultimately achieving macro-micro mechanical bite and significantly improving the mechanical properties of the joint.

[0048] As a supplement to the technical solution of the present invention, the prefabricated grooves 9 on the metal plate A6 are provided with one or more groups. When there are multiple groups of prefabricated grooves 9, the multiple groups of prefabricated grooves 9 are parallel to each other and the distance between two adjacent groups of prefabricated grooves 9 is 1-2 mm.

[0049] The trough body can be intermittent or continuous, preferably continuous, because the use of a continuous trough body can increase the macro welding and riveting composite connection area and improve the overall strength of the welded joint.

[0050] As a supplement to the above technical solution, the specific structure of the prefabricated groove 9 can be any shape. When only one group of prefabricated grooves 9 is provided, the prefabricated grooves 9 are preferably dovetail groove structures. Preferably, the corners of the dovetail grooves are rounded, so that the metal after the welding wire 2 is melted can fully fill the prefabricated grooves 9 and prevent the generation of defects such as pores. Figure 2 As shown, the corner position in the dovetail groove is set to a rounded structure so that the welding wire 2 can fully fill the dovetail groove after melting. In addition, in order to ensure that the liquid metal after the welding wire 2 melts fills the dovetail groove and can smoothly flow into the area between the metal plate A6 and the metal plate B8, as shown in FIG. Figure 2 As shown, the height of the upper end surface of the metal plate A6 located on the left side of the dovetail groove is higher than the height of the upper end surface of the metal plate A6 located on the right side of the dovetail groove.

[0051] As a preferred technical solution of the present invention, when the precast grooves 9 are opened in 3 groups in total, the 3 groups of precast grooves 9 are opened in relative parallel, and the precast grooves 9 can be straight or curved. When the precast grooves 9 are curved structures, the contact area between the metal in the precast grooves 9 and the metal in the weld area can be further increased, thereby increasing the strength of the welded joint.

[0052] like Figure 3 As shown, the three groups of prefabricated grooves 9 are respectively prefabricated groove 9A, prefabricated groove 9B, and prefabricated groove 9C in order of distance from the welding area from far to near, wherein the prefabricated groove 9A and the prefabricated groove 9C are both concave arc groove structures, and the prefabricated groove 9B is a dovetail groove structure. The spacing between two adjacent sections of the prefabricated groove 9 is 1-2 mm.

[0053] As the preferred technical solution of the present invention, when a MIG welder is selected, the welding working parameters of MIG welding are specifically as follows: the dry extension length of the MIG welding gun 1 is set at 10-20 mm, the argon shielding gas flow rate is 18-22 L / min, the welding current is 20-200 A, the welding speed is 1.5-4 mm / s, and the wire feeding speed is 10-28 mm / s.

[0054] When a TIG welder is selected, the specific welding working parameters of TIG welding are: the distance between the tungsten tip of the TIG welding gun and the horizontal plane of the stainless steel plate is 0.5-2.5mm, the argon shielding gas flow rate is 18-22L / min, the welding current is 20-200A, the welding speed is 1.5-4mm / s, and the wire feeding speed is 10-28mm / s.

[0055] As a preferred technical solution of the present invention, the specific welding working parameters of the friction stir welding are: rotation speed 400-1500r / min, shoulder pressure 0.1mm, welding speed 1.5-4mm / s, stirring needle inclination 2°-2.5°.

[0056] As a preferred technical solution of the present invention, the friction stir welding adopts static shoulder friction stir welding. After the friction stir treatment, the static shoulder of the stirring head 4 reduces the peak temperature of A and the metal plate B8, improves the weld formation, and releases the residual stress inside the weld.

[0057] As a preferred technical solution of the present invention, the metal plate A6 is a copper plate, and the metal plate B8 is an aluminum alloy plate.

[0058] As a supplement to the technical solution of the present invention, the metal plate A6 is a titanium alloy plate, and the metal plate B8 is an aluminum alloy plate.

[0059] The present invention also discloses a method for using the above-mentioned device, which specifically includes the following steps: first, start the welding gun 1, and the liquid metal after the welding wire 2 is melted fills the prefabricated groove 9 and then flows into the area between the metal plate A6 and the metal plate B8 to form a filling metal. When the metal located in the area between the metal plate A6 and the metal plate B8 is in a semi-solid state, the stirring head 4 of the stir friction welding intervenes to complete the welding of the metal plate A6 and the metal plate B8; during the welding process, the stirring head 4 of the stir friction welding moves in the same direction as the welding gun 1 at the same speed; after the welding is completed, first turn off the welding gun 1, then withdraw the stirring head 4 of the stir friction welding, and turn off the stir friction welding machine.

[0060] To facilitate the understanding of the technical solution, the present invention provides the following embodiments, specifically selecting 6061 grade aluminum alloy for welding, but is not limited to the above grade aluminum alloy. The welding method disclosed in the present invention is also applicable to the welding of other grades of aluminum alloy and copper.

[0061] Embodiment 1:

[0062] S1. Select 6061 aluminum alloy plates and pure copper plates of the same thickness, and clean the plates by mechanical grinding to keep their surfaces flat and clean.

[0063] S2. Fix the 6061 aluminum alloy plate and the copper plate on the workbench by means of a clamp. The welding joint is a butt joint. To ensure sufficient metallurgical reaction on the aluminum alloy plate side, a 40° groove is provided on the 6061 aluminum alloy plate, and a prefabricated groove 9 of a dovetail groove structure is provided on the surface of the copper plate. The groove on the 6061 aluminum alloy plate and the prefabricated groove 9 on the surface of the copper plate are wiped with alcohol.

[0064] S3. MIG welding is used for brazing. A MIG welding gun 1 is set above the prefabricated groove 9 area of ​​the copper plate, and the dry extension length is set at 12 mm. A stirring head 4 for stir friction welding is set above the prefabricated groove 9 and the area between the copper plate and the aluminum alloy plate.

[0065] The distance between the MIG welding gun 1 and the stirring head 4 of the stir friction welding is 25 mm, which can enable the liquid metal after the melting of the welding wire 2 to fill the prefabricated groove 9 and then flow into the area between the copper plate and the aluminum alloy plate. When the weld metal is in a semi-solid state, stir friction welding can reduce the damage to the stirring needle and improve the welding quality.

[0066] In the above welding process, the specific welding process parameters of MIG are: argon shielding gas flow rate 20L / min, welding current 70A, welding speed 1.5mm / s, and wire feeding speed 14mm / s.

[0067] The specific welding process parameters of friction stir welding are: rotation speed 700r / min, shoulder pressure 0.1mm, welding speed 1.5mm / s, and stirring needle inclination angle 2°.

[0068] S4. After the welding is completed, first turn off the MIG welding gun 1, then withdraw the stirring head 4 of the friction stir welding, and turn off the friction stir welding machine.

[0069] The tensile strength of the aluminum-copper welded rivet joints was tested using a universal tensile testing machine, and the average strength of the aluminum-copper welded rivet joints obtained was about 172 MPa.

[0070] Embodiment 2:

[0071] The metal plate A is a TC4 titanium alloy plate, and the metal plate B is an aluminum alloy plate. The aluminum alloy plate is specifically a 5A06 grade aluminum alloy for welding, but is not limited to the above grades of aluminum alloys. The welding method disclosed in the present invention is also applicable to the welding of other grades of aluminum alloys and stainless steel. The welding process specifically includes the following steps:

[0072] S1. Select 5A06 aluminum alloy plates and TC4 plates of the same thickness, and clean the plates by mechanical grinding to keep their surfaces flat and clean.

[0073] S2. Fix the 5A06 aluminum alloy plate and TC4 plate on the workbench by means of a clamp. The welding joint is a butt joint. To ensure sufficient metallurgical reaction on the aluminum alloy plate side, a 40° groove is provided on the 5A06 aluminum alloy plate. Three sections of prefabricated grooves are provided on the plate surface. From left to right, the spacing between each section is 2mm and 1mm respectively. The groove on the 5A06 aluminum alloy plate and the prefabricated groove on the surface of the TC4 plate are wiped with alcohol.

[0074] S3. TIG welding is used for brazing. A TIG welding gun is set above the prefabricated groove area of ​​the TC4 titanium alloy plate, so that the distance between the tungsten electrode tip of the TIG welding gun and the horizontal plane of the TC4 plate is 1 mm. A stirring head for stir friction welding is set above the prefabricated groove and the area between the TC4 plate and the aluminum alloy plate.

[0075] The distance between the TIG welding gun and the stirring head of the stir friction welding is 25mm, which can enable the liquid metal after the welding wire is melted to fill the prefabricated groove and then flow into the area between the TC4 plate and the aluminum alloy plate. When the weld metal is in a semi-solid state, stir friction welding can reduce the damage of the stirring needle and improve the welding quality.

[0076] In the above welding process, the specific welding process parameters of TIG are: argon shielding gas flow rate 20L / min, welding current 80A, welding speed 2mm / s, and wire feeding speed 10mm / s.

[0077] The specific welding process parameters of friction stir welding are: rotation speed 700r / min, shoulder pressure 0.1mm, welding speed 2mm / s, and stirring needle inclination angle 2°.

[0078] S4. After welding is completed, first turn off the TIG welding gun, then withdraw the stirring head of the friction stir welding, and turn off the friction stir welding machine.

[0079] The tensile strength of the aluminum-titanium welded rivet joints was tested using a universal tensile testing machine, and the average strength of the aluminum-titanium welded rivet joints obtained was about 236 MPa.

[0080] Comparative Example 1:

[0081] S1. Select 6061 aluminum alloy plates and copper plates of the same thickness, and clean the plates by mechanical grinding to keep their surfaces flat and clean.

[0082] S2. Fix the 6061 plate and the copper plate by a clamp, the welding joint is a butt joint, a 40° groove is opened on the 6061 plate and the copper, and the grooves on the 6061 plate and the copper are wiped with alcohol;

[0083] S3. Set MIG welding gun 1 just above the gap between the copper plate and the 6061 plate, and set the dry extension length to 12 mm;

[0084] S4. During the formal welding, the MIG welding gun 1 is started to fill the groove of the aluminum alloy plate and the copper plate with the welding wire 2. The welding process parameters of the MIG welding are the same as those in Example 1.

[0085] S5. Welding is finished and the MIG welding gun 1 is turned off.

[0086] S6. The tensile strength of the aluminum-copper brazing joint was tested using a universal tensile testing machine. The average strength of the aluminum-copper brazing joint was about 111 MPa.

[0087] By comparing Implementation 1 with Comparative Example 1, the tensile strength of the aluminum-copper joint prepared by the heterogeneous metal welding device of the present invention is increased by about 55%.

[0088] Comparative Example 2:

[0089] S1. Select 5A06 aluminum alloy plates and TC4 plates of the same thickness, and clean the plates by mechanical grinding to keep their surfaces flat and clean.

[0090] S2. Fix the 5A06 plate and TC4 plate by a fixture. The welding joint is a butt joint. A 40° groove is opened on both the 5A06 plate and TC4. The grooves on the 5A06 plate and TC4 are wiped with alcohol.

[0091] S3. Set a TIG welding gun just above the gap between the TC4 plate and the 5A06 plate, with the distance between the tungsten electrode tip of the TIG welding gun and the horizontal plane of the titanium plate being 1 mm;

[0092] S4. During the formal welding, the TIG welding gun is started to fill the groove of the aluminum alloy plate and the TC4 plate with welding wire. The welding process parameters of TIG welding are the same as those in Example 2.

[0093] S5. Welding is finished and the TIG welding gun is turned off.

[0094] The tensile strength of the aluminum-titanium fusion brazing joint was tested by a universal tensile testing machine, and the average strength of the aluminum-titanium fusion brazing joint was about 127 MPa. Comparing Example 2 with Comparative Example 2, the aluminum-titanium joint was prepared by using the heterogeneous metal welding device of the present invention, and the tensile strength of the joint was increased by about 86%.

[0095] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A heterogeneous metal welding device, including a friction stir welding machine and a brazing welding machine, characterized in that: The friction stir welding machine includes a stirring head, and the brazing welding machine includes a welding gun, a workbench, a welding wire, a metal plate A, and a metal plate B; The metal plate A and the metal plate B are arranged on a workbench in the form of a butt joint, the upper surface of the metal plate A is provided with a prefabricated groove, and the prefabricated groove extends along the direction of the weld; the metal plate B is provided with a groove; The welding gun and welding wire are both arranged above the prefabricated groove on the metal plate A, the stirring head is arranged above the area between the metal plate A and the metal plate B, and the stirring head covers the prefabricated groove on the metal plate A and the groove on the metal plate B, the length direction of the weld between the metal plate A and the metal plate B is perpendicular to the plane formed by the central axis of the stirring head and the plane where the workbench is located, and the welding gun is located in front of the stirring head; The specific time when the stirring head intervenes from the starting point of the area between the metal plate A and the metal plate B is: the liquid metal after the welding wire melts fills the prefabricated groove and then flows into the area between the metal plate A and the metal plate B to form the filling metal, and the stirring head intervenes when the filling metal is in a semi-solid state; During welding, the stirring head and the welding gun move at the same speed and in the same direction; The metal plate A is a copper plate, a titanium alloy plate or a steel plate, and the metal plate B is an aluminum alloy plate.

2. A heterogeneous metal welding device according to claim 1, characterized in that: The groove opening angle on the metal plate B is 30°-40°.

3. The heterogeneous metal welding device according to claim 1, characterized in that: The metal plate A is provided with one or more groups of prefabricated grooves. When there are multiple groups of prefabricated grooves, the multiple groups of prefabricated grooves are parallel to each other and the distance between two adjacent groups of prefabricated grooves is 1-2 mm.

4. A heterogeneous metal welding device according to claim 3, characterized in that: When the prefabricated grooves are a group, the prefabricated grooves are dovetail groove structures.

5. The heterogeneous metal welding device according to claim 1, characterized in that: The prefabricated groove on the metal plate A is a continuous and uninterrupted groove structure.

6. The heterogeneous metal welding device according to claim 1, characterized in that: When a MIG welder is used, the specific welding parameters of MIG welding are: the dry extension length of the MIG welding gun is set at 10-20 mm, the argon shielding gas flow rate is 18-22 L / min, the welding current is 20-200 A, the welding speed is 1.5-4 mm / s, and the wire feeding speed is 10-28 mm / s; When a TIG welder is selected, the specific welding working parameters of TIG welding are: the distance between the tungsten electrode tip of the TIG welding gun and the horizontal plane of the metal plate A is 0.5-2.5 mm, the argon shielding gas flow rate is 18-22 L / min, the welding current is 20-200 A, the welding speed is 1.5-4 mm / s, and the wire feeding speed is 10-28 mm / s.

7. The heterogeneous metal welding device according to claim 1, characterized in that: The specific welding parameters of friction stir welding are: rotation speed 400-1500 r / min, shoulder pressure 0.1 mm, welding speed 1.5-4 mm / s, and stirring needle inclination angle 2°-2.5°.

8. The heterogeneous metal welding device according to claim 1, characterized in that: Friction stir welding uses static shoulder friction stir welding.

Images